Polymerisable Liquid Crystal Material and Polymerised Liquid Crystal Film

ABSTRACT

The invention relates to a polymerisable LC material comprising one or more di- or multireactive mesogenic compounds and one or more compounds of formula TRI,wherein the individual radicals have one of the meaning as given in the claims. Furthermore, the present invention relates also to a method for its preparation, a polymer film with improved thermal durability and UV stability obtainable from the corresponding polymerisable LC material, to a method of preparation of such polymer film, and to the use of such polymer film and said polymerisable LC material for optical, electro-optical, decorative or security devices.

FIELD OF INVENTION

The invention relates to a polymerisable LC material comprising one ormore di- or multireactive mesogenic compounds and one or more compoundsof formula TRI,

wherein the individual radicals have one of the meaning as given in theclaims. Furthermore, the present invention relates also to a method forits preparation, a polymer film with improved thermal durability and UVstability obtainable from a corresponding polymerisable LC material, toa method of preparation of such polymer film, and to the use of suchpolymer film and said polymerisable LC material for optical,electro-optical, decorative or security devices.

BACKGROUND AND PRIOR ART

Polymerizable liquid crystal materials are known in prior art for thepreparation of anisotropic polymer films with uniform orientation. Thesefilms are usually prepared by coating a thin layer of a polymerizableliquid crystal mixture onto a substrate, aligning the mixture intouniform orientation and polymerizing the mixture. The orientation of thefilm can be planar, i.e. where the liquid crystal molecules are orientedsubstantially parallel to the layer, homeotropic (rectangular orperpendicular to the layer) or tilted.

Such optical films are described, for example, in EP 0940707 B1, EP 0888565 B1 and GB 2329393 B1.

Polymerisable liquid crystal (LC) materials, while stable at roomtemperature, can degrade when subjected to increased temperatures. Forexample, when heated for a period of time the optical properties such asdispersion or retardance decreases and as such, the performance of theoptical film degrades over time. This can be attributed, in particular,to a low degree of polymerisation and a corresponding high content ofresidual free radicals in the polymer, polymer shrinkage, and/orthermo-oxidative degradation.

Thermo-oxidative degradation is the breakdown of a polymer networkcatalysed by oxidation at high temperatures. As commonly known,antioxidant additives, or short antioxidants, can be used to reduce thethermo-oxidative degradation of polymers when subjected to increasedtemperatures. This is especially important when optical films areutilized for an in-cell application due to the high temperatures. Inparticular, the optical film has to endure when annealing the polyimidelayer in the LC cell. In this regard, the documents WO 2009/86911 A1 andJP 5354238 B1 describe polymerisable liquid crystal (LC) materialscomprising the commercially available antioxidant Irganox®1076.

The above-described materials have distinct disadvantages, such as, theUV stability or thermal durability of the resulting polymer films isstill not high enough, their transparency to VIS-light is limited, theyrequire the utilization of further additives, or their applicationbandwidth is limited, due to the utilized LC material.

Therefore, there is still the need for new and preferably improved,polymerisable liquid crystal materials or mixtures, which do not exhibitthe drawbacks of prior art materials or if so, do only exhibit them to aless extent.

Advantageously, such polymerisable LC material, should preferably beapplicable for the preparation of different, uniform aligned polymernetworks, such as polymer films or polymer network LC applications, andshould, in particular at the same time,

-   -   show a favourable adhesion to a substrate,    -   be highly transparent to VIS-light,    -   exhibit a reduced yellow colouration over time (yellowing) and    -   show a favourable high temperature stability or durability, and        in addition,    -   show a favourable high UV stability or durability, and in        addition,    -   the uniform aligned polymer films should be produced by        compatible, commonly known methods for the mass production.

Other aims of the present invention are immediately evident to theperson skilled in the art from the following detailed description.

Surprisingly, the inventors of the present invention have found that oneor more, preferably all of the above requirements aims can be achieved,preferably at the same time, by using a polymerisable LC materialaccording to claim 1.

SUMMARY OF THE INVENTION

The present invention relates to a polymerizable LC material comprisingat least one di- or multireactive mesogenic compound and one or morecompounds of formula TRI,

wherein the individual radicals, independently of each other and on eachoccurrence identically or differently, have the following meanings:

-   R¹ to R⁹ each represent a hydrogen atom, a hydroxy group, a halogen    atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group    having 3 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon    atoms, or an aryl group having 6 to 20 carbon atoms;-   R^(a) denotes a straight chain or branched alkyl having 1 to 20,    preferably 1 to 12 C atoms, which is optionally mono- or    polysubstituted by F, Cl, Br, I or CN and in which, in addition, one    or more non-adjacent CH₂ groups may each be replaced, independently    of one another,    -   by —O—, —S—, —NH—, —NR^(xx)—, —SiR^(xx)R^(yy)—, —CO—, —COO—,        —OCO—, —OCO—O—, —S—CO—, —CO—S—, —NR^(xx)—CO—O—, —O—CO—NR^(xx)—,        —NR^(xx)—CO—NR^(yy)—, —CH═CH— or —C≡C— in such a way that O        and/or S atoms are not linked directly to one another,-   R^(xx) and R^(yy) each, independently of one another, denote H or    alkyl having 1 to 12 C atoms.

Further, the invention also relates to a corresponding method ofproduction for the polymerisable LC material.

The invention further relates to a polymer network or polymer filmobtainable, preferably obtained, from the polymerisable LC material, asdescribed above and below and to a method of production of a polymerfilm, as described above and below.

The invention further relates to a method of increasing the UV stabilityof a polymer film, obtainable, preferably obtained, from a polymerisableLC material as described above and below, by adding a compound offormula TRI to the LC material before polymerisation.

The invention further relates to the use of a polymer network or polymerfilm or polymerisable LC material, as described above and below, inoptical, electrooptical, information storage, decorative and securityapplications, like liquid crystal displays, projection systems,polarisers, compensators, alignment layers, circular polarisers, colourfilters, decorative images, liquid crystal pigments, reflective filmswith spatially varying reflection colours, multicolour images,non-forgeable documents like identity or credit cards or banknotes.

The invention further relates to an optical component or device,polariser, patterned retarder, compensator, alignment layer, circularpolariser, colour filter, decorative image, liquid crystal lens, liquidcrystal pigment, reflective film with spatially varying reflectioncolours, multicolour image for decorative or information storage,comprising at least one polymer network or polymer film or polymerisableLC material, as described above and below

The invention further relates to a liquid crystal display comprising atleast one polymer network or polymer film or polymerisable LC materialor an optical component, as described above and below.

The invention further relates to authentification, verification orsecurity marking, coloured or multicolour image for security use,non-forgeable object or document of value like an identity or creditcard or a banknote, comprising a polymer network or polymer film orpolymerisable LC material or an optical component as described above andbelow.

Terms and Definitions

As used herein, the term “polymer” will be understood to mean a moleculethat encompasses a backbone of one or more distinct types of repeatingunits (the smallest constitutional unit of the molecule) and isinclusive of the commonly known terms “oligomer”, “copolymer”,“homopolymer” and the like. Further, it will be understood that the termpolymer is inclusive of, in addition to the polymer itself, residuesfrom initiators, catalysts, and other elements attendant to thesynthesis of such a polymer, where such residues are understood as notbeing covalently incorporated thereto. Further, such residues and otherelements, while normally removed during post polymerisation purificationprocesses, are typically mixed or co-mingled with the polymer such thatthey generally remain with the polymer when it is transferred betweenvessels or between solvents or dispersion media.

The term “(meth)acrylic polymer” as used in the present inventionincludes a polymer obtained from acrylic monomers, a polymer obtainablefrom methacrylic monomers, and a corresponding co-polymer obtainablefrom mixtures of such monomers.

The term “polymerisation” means the chemical process to form a polymerby bonding together multiple polymerisable groups or polymer precursors(polymerisable compounds) containing such polymerisable groups.

The terms “film” and “layer” include rigid or flexible, self-supportingor freestanding films with mechanical stability, as well as coatings orlayers on a supporting substrate or between two substrates.

The term “liquid crystal” or “LC” relates to materials havingliquid-crystalline mesophases in some temperature ranges (thermotropicLCs) or in some concentration ranges in solutions (lyotropic LCs). Theyobligatorily contain mesogenic compounds.

The terms “mesogenic compound” and “liquid crystal compound” mean acompound comprising one or more calamitic (rod- or board/lath-shaped) ordiscotic (disk-shaped) mesogenic groups. The term “mesogenic group”means a group with the ability to induce liquid-crystalline phase (ormesophase) behaviour. The compounds comprising mesogenic groups do notnecessarily have to exhibit a liquid-crystalline mesophase themselves.It is also possible that they show liquid-crystalline mesophases only inmixtures with other compounds, or when the mesogenic compounds ormaterials, or the mixtures thereof, are polymerised. This includeslow-molecular-weight non-reactive liquid-crystalline compounds, reactiveor polymerisable liquid-crystalline compounds, and liquid-crystallinepolymers.

A calamitic mesogenic group is usually comprising a mesogenic coreconsisting of one or more aromatic or non-aromatic cyclic groupsconnected to each other directly or via linkage groups, optionallycomprising terminal groups attached to the ends of the mesogenic core,and optionally comprising one or more lateral groups attached to thelong side of the mesogenic core, wherein these terminal and lateralgroups are usually selected e.g. from carbyl or hydrocarbyl groups,polar groups like halogen, nitro, hydroxy, etc., or polymerisablegroups.

The term “reactive mesogen” means a polymerisable mesogenic or liquidcrystal compound, preferably a monomeric compound. These compounds canbe used as pure compounds or as mixtures of reactive mesogens with othercompounds functioning as photoinitiators, inhibitors, surfactants,stabilizers, chain transfer agents, non-polymerisable compounds, etc.

Polymerisable compounds with one polymerisable group are also referredto as “monoreactive” compounds, compounds with two polymerisable groupsas “direactive” compounds, and compounds with more than twopolymerisable groups as “multireactive” compounds. Compounds without apolymerisable group are also referred to as “non-reactive ornon-polymerisable” compounds.

The term “non-mesogenic compound or material” means a compound ormaterial that does not contain a mesogenic group as defined above.

Visible light is electromagnetic radiation that has wavelength in arange from about 400 nm to about 740 nm. Ultraviolet (UV) light iselectromagnetic radiation with a wavelength in a range from about 200 nmto about 450 nm.

The Irradiance (E_(e)) or radiation power is defined as the power ofelectromagnetic radiation (dθ) per unit area (dA) incident on a surface:

E _(e) =dθ/dA.

The radiant exposure or radiation dose (H_(e)), is as the irradiance orradiation power (E_(e)) per time (t):

H _(e) =E _(e) ·t.

All temperatures, such as, for example, the melting point T(C,N) orT(C,S), the transition from the smectic (S) to the nematic (N) phaseT(S,N) and the clearing point T(N,I) of the liquid crystals, are quotedin degrees Celsius. All temperature differences are quoted indifferential degrees.

The term “clearing point” means the temperature at which the transitionbetween the mesophase with the highest temperature range and theisotropic phase occurs.

The term “director” is known in prior art and means the preferredorientation direction of the long molecular axes (in case of calamiticcompounds) or short molecular axes (in case of discotic compounds) ofthe liquid-crystalline or RM molecules. In case of uniaxial ordering ofsuch anisotropic molecules, the director is the axis of anisotropy.

The term “alignment” or “orientation” relates to alignment(orientational ordering) of anisotropic units of material such as smallmolecules or fragments of big molecules in a common direction named“alignment direction”. In an aligned layer of liquid-crystalline or RMmaterial the liquid-crystalline director coincides with the alignmentdirection so that the alignment direction corresponds to the directionof the anisotropy axis of the material.

The terms “uniform orientation” or “uniform alignment” of aliquid-crystalline or RM material, for example in a layer of thematerial, mean that the long molecular axes (in case of calamiticcompounds) or the short molecular axes (in case of discotic compounds)of the liquid-crystalline or RM molecules are oriented substantially inthe same direction. In other words, the lines of liquid-crystallinedirector are parallel.

The term “homeotropic structure” or “homeotropic orientation” refers toa film wherein the optical axis is substantially perpendicular to thefilm plane.

The term “planar structure” or “planar orientation” refers to a filmwherein the optical axis is substantially parallel to the film plane.

The term “negative (optical) dispersion” refers to a birefringent orliquid crystalline material or layer that displays reverse birefringencedispersion where the magnitude of the birefringence (Δn) increases withincreasing wavelength (λ). I.e. |Δn (450)|<|Δn (550)|, or Δn (450)/Δn(550)<1, where Δn (450) and Δn (550) are the birefringence of thematerial measured at wavelengths of 450 nm and 550 nm respectively. Incontrast, positive (optical) dispersion” means a material or layerhaving |Δn (450)|>|Δn (550)| or Δn (450)/Δn (550)>1. See also forexample A. Uchiyama, T. Yatabe “Control of Wavelength Dispersion ofBirefringence for Oriented Copolycarbonate Films Containing Positive andNegative Birefringent Units”. J. Appl. Phys. Vol. 42 pp 6941-6945(2003).

Since the optical retardation at a given wavelength is defined as theproduct of birefringence and layer thickness as described above[R(λ)=Δn(λ)·d], the optical dispersion can be expressed either as the“birefringence dispersion” by the ratio Δn(450)/Δn(550), or as“retardation dispersion” by the ratio R(450)/R(550), wherein R(450) andR(550) are the retardation of the material measured at wavelengths of450 nm and 550 nm respectively. Since the layer thickness d does notchange with the wavelength, R (450)/R (550) is equal to Δn (450)/Δn(550). Thus, a material or layer with negative or reverse dispersion hasR (450)/R (550)<1 or |R (450)|<|R (550)|, and a material or layer withpositive or normal dispersion has R (450)/R (550)>1 or |R (450)|>|R(550)|.

In the present invention, unless stated otherwise “optical dispersion”means the retardation dispersion i.e. the ratio R (450)/R (550).

The term “high dispersion” means that the absolute value of thedispersion shows a large deviation from 1, whereas the term “lowdispersion” means that the absolute value of the dispersion shows asmall deviation from 1. Thus “high negative dispersion” means that thedispersion value is significantly smaller than 1, and “low negativedispersion” means that the dispersion value is only slightly smallerthan 1.

The retardation (R(λ)) of a material can be measured using aspectroscopic ellipsometer, for example the M2000 spectroscopicellipsometer manufactured by J. A. Woollam Co., This instrument iscapable of measuring the optical retardance in nanometres of abirefringent sample e.g. Quartz over a range of wavelengths typically,370 nm to 2000 nm. From this data, it is possible to calculate thedispersion (R(450)/R(550) or Δn(450)/Δn(550)) of a material.

A method for carrying out these measurements was presented at theNational Physics Laboratory (London, UK) by N. Singh in October 2006 andentitled “Spectroscopic Ellipsometry, Part1—Theory and Fundamentals,Part 2—Practical Examples and Part 3—measurements”. In accordance withthe measurement procedures described Retardation Measurement (RetMeas)Manual (2002) and Guide to WVASE (2002) (Woollam Variable AngleSpectroscopic Ellipsometer) published by J. A. Woollam Co. Inc (Lincoln,Nebr., USA). Unless stated otherwise, this method is used to determinethe retardation of the materials, films and devices described in thisinvention.

The term “A plate” refers to an optical retarder utilizing a layer ofuniaxially birefringent material with its extraordinary axis orientedparallel to the plane of the layer.

The term “C plate” refers to an optical retarder utilizing a layer ofuniaxially birefringent material with its extraordinary axis orientedperpendicular to the plane of the layer.

In A/C-plates comprising optically uniaxial birefringent liquid crystalmaterial with uniform orientation, the optical axis of the film is givenby the direction of the extraordinary axis. An A (or C) plate comprisingoptically uniaxial birefringent material with positive birefringence isalso referred to as “positive A (or C) plate” or “+A (or +C) plate”.

An A (or C) plate comprising a film of optically uniaxial birefringentmaterial with negative birefringence, such as discotic anisotropicmaterials is also referred to as “negative A (or C) plate” or “−A (or C)plate” depending on the orientation of the discotic materials. A filmmade from a cholesteric calamitic material with a reflection band in theUV part of the spectrum also has the optics of a negative C plate.

The birefringence Δn is defined as follows

Δn=n _(e) −n _(o)

wherein n_(e) is the extraordinary refractive index and n_(o) is theordinary refractive index, and the average refractive index n_(av.) isgiven by the following equation:

n _(av.)=((2n _(o) ² +n _(e) ²)/3)^(1/2)

The average refractive index n_(av.) and the ordinary refractive indexn_(o) can be measured using an Abbe refractometer. Δn can then becalculated from the above equations.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

All physical properties have been and are determined according to “MerckLiquid Crystals, Physical Properties of Liquid Crystals”, StatusNovember 1997, Merck KGaA, Germany and are given for a temperature of20° C., unless explicitly stated otherwise. The optical anisotropy (Δn)is determined at a wavelength of 589.3 nm

In case of doubt the definitions as given in C. Tschierske, G. Pelzl andS. Diele, Angew. Chem. 2004, 116, 6340-6368 shall apply.

Unless explicitly stated otherwise in the given generic formulae, thefollowing terms have the following meanings:

“Carbyl group” denotes a mono- or polyvalent organic group containing atleast one carbon atom which either contains no further atoms (such as,for example, —C≡C—) or optionally contains one or more further atoms,such as, for example, N, O, S, P, Si, Se, As, Te or Ge (for examplecarbonyl, etc.). “Hydrocarbyl group” denotes a carbyl group, whichadditionally contains one or more H atoms and optionally one or moreheteroatoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge.

A carbyl or hydrocarbyl group can be a saturated or unsaturated group.Unsaturated groups are, for example, aryl, alkenyl, or alkinyl groups. Acarbyl or hydrocarbyl group having more than 3 C atoms can be straightchain, branched and/or cyclic and may contain spiro links or condensedrings.

Preferred carbyl and hydrocarbyl groups are optionally substitutedalkyl, alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to25, particularly preferably 1 to 18 C atoms, optionally substituted arylor aryloxy having 6 to 40, preferably 6 to 25 C atoms, or optionallysubstituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy,arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxyhaving 6 to 40, preferably 6 to 25 C atoms. Further preferred carbyl andhydrocarbyl groups are C₁-C₄₀ alkyl, C₂-C₄₀ alkenyl, C₂-C₄₀ alkinyl,C₃-C₄₀ allyl, C₄-C₄₀ alkyldienyl, C₄-C₄₀ polyenyl, C₆-C₄₀ aryl, C₆-C₄₀alkylaryl, C₆-C₄₀ arylalkyl, C₆-C₄₀ alkylaryloxy, C₆-C₄₀ aryl-alkyloxy,C₂-C₄₀ heteroaryl, C₄-C₄₀ cycloalkyl, C₄-C₄₀ cycloalkenyl, etc.Particular preference is given to C₁-C₂₂ alkyl, C₂-C₂₂ alkenyl, C₂-C₂₂alkinyl, C₃-C₂₂ allyl, C₄-C₂₂ alkyldienyl, C₆-C₁₂ aryl, C₆-C₂₀arylalkyl, and C₂-C₂₀ heteroaryl.

Further preferred carbyl and hydrocarbyl groups are straight-chain,branched or cyclic alkyl radicals having 1 to 40, preferably 1 to 25 Catoms, more preferably 1 to 12 C atoms, which are unsubstituted or mono-or polysubstituted by F, Cl, Br, I or CN and in which one or morenon-adjacent CH₂ groups may each be replaced, independently of oneanother, by —C(R^(x))═C(R^(x))—, —C≡C—, —N(R^(x))—, —O—, —S—, —CO—,—CO—O—, —O—CO—, —O—CO—O— in such a way that O and/or S atoms are notlinked directly to one another.

Above, R^(x) preferably denotes H, halogen, a straight-chain, branchedor cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, oneor more non-adjacent C atoms may be replaced by —O—, —S—, —CO—, —CO—O—,—O—CO—, —O—CO—O—, and in which one or more H atoms may be replaced byfluorine, an optionally substituted aryl or aryloxy group having 6 to 40C atoms or an optionally substituted heteroaryl or heteroaryloxy grouphaving 2 to 40 C atoms.

Preferred alkyl groups are, for example, methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl,s-pentyl, n-hexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl,n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl,2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc.

Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl,pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl,octenyl, cyclooctenyl, etc.

Preferred alkinyl groups are, for example, ethynyl, propynyl, butynyl,pentynyl, hexynyl, octynyl, etc.

Preferred alkoxy groups are, for example, methoxy, ethoxy,2-methoxy-ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy,t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptyloxy, n-octyloxy,n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, etc.

Preferred amino groups are, for example, dimethylamino, methylamino,methylphenylamino, phenylamino, etc.

Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e. theycan have one ring (such as, for example, phenyl) or two or more rings,which may also be fused (such as, for example, naphthyl) or covalentlylinked (such as, for example, biphenyl), or contain a combination offused and linked rings. Heteroaryl groups contain one or moreheteroatoms, preferably selected from O, N, S, and Se.

Particular preference is given to mono-, bi-, or tricyclic aryl groupshaving 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groupshaving 2 to 25 C atoms, which optionally contain fused rings, and whichare optionally substituted. Preference is furthermore given to 5-, 6-,or 7-membered aryl and heteroaryl groups, in which, in addition, one ormore CH groups may be replaced by N, S, or O in such a way that O atomsand/or S atoms are not linked directly to one another.

Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl,[1,1′:3′,1″ ]terphenyl-2′-yl, naphthyl, anthracene, binaphthyl,phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene,pentacene, benzo-pyrene, fluorene, indene, indenofluorene,spirobifluorene, etc.

Preferred heteroaryl groups are, for example, 5-membered rings, such aspyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole,furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole,1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole,1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole,1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings, such aspyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine,1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine,1,2,3,5-tetrazine, or condensed groups, such as indole, iso-indole,indolizine, indazole, benzimidazole, benzotriazole, purine,naphth-imidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole,quinoxa-linimidazole, benzoxazole, naphthoxazole, anthroxazole,phenanthroxa-zole, isoxazole, benzothiazole, benzofuran, isobenzofuran,dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline,benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine,phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine,quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline,phenanthridine, phenan-throline, thieno[2,3b]thiophene,thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene,dibenzothiophene, benzothiadiazothiophene, or combinations of thesegroups. The heteroaryl groups may also be substituted by alkyl, alkoxy,thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups.

The (non-aromatic) alicyclic and heterocyclic groups encompass bothsaturated rings, i.e. those that contain exclusively single bonds, andpartially unsaturated rings, i.e. those that may also contain multiplebonds. Heterocyclic rings contain one or more heteroatoms, preferablyselected from Si, O, N, S, and Se.

The (non-aromatic) alicyclic and heterocyclic groups can be monocyclic,i.e. contain only one ring (such as, for example, cyclohexane), orpolycyclic, i.e. contain a plurality of rings (such as, for example,decahydro-naphthalene or bicyclooctane). Particular preference is givento saturated groups. Preference is furthermore given to mono-, bi-, ortricyclic groups having 3 to 25 C atoms, which optionally contain fusedrings, and which are optionally substituted. Preference is furthermoregiven to 5-, 6-, 7- or 8-membered carbocyclic groups in which, inaddition, one or more C atoms may be replaced by Si and/or one or moreCH groups may be replaced by N and/or one or more non-adjacent CH₂groups may be replaced by —O— and/or —S—.

Preferred alicyclic and heterocyclic groups are, for example, 5-memberedgroups, such as cyclopentane, tetrahydrofuran, tetrahydrothiofuran,pyrrolidine, 6-membered groups, such as cyclohexane, silinane,cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane,1,3-dithiane, piperidine, 7-membered groups, such as cycloheptane, andfused groups, such as tetrahydronaphthalene, decahydronaphthalene,indane, bicyclo[1.1.1]-pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl,spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindane-2,5-diyl.

The aryl, heteroaryl, (non-aromatic) alicyclic and heterocyclic groupsoptionally have one or more substituents, which are preferably selectedfrom the group comprising silyl, sulfo, sulfonyl, formyl, amine, imine,nitrile, mercapto, nitro, halogen, C₁₋₁₂ alkyl, C₆₋₁₂ aryl, C₁₋₁₂alkoxy, hydroxyl, or combinations of these groups.

Preferred substituents are, for example, solubility-promoting groups,such as alkyl or alkoxy, electron-withdrawing groups, such as fluorine,nitro or nitrile, or substituents for increasing the glass transitiontemperature (Tg) in the polymer, in particular bulky groups, such as,for example, t-butyl or optionally substituted aryl groups.

Preferred substituents, also referred to as “L” below, are, for example,F, Cl, Br, I, —OH, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)N(R^(x))₂,—C(═O)Y^(x), —C(═O)R^(x), —C(═O)OR^(x), —N(R^(x))₂, in which R^(x) hasthe above-mentioned meaning, and above Y^(x) denotes halogen, optionallysubstituted silyl, optionally substituted aryl or heteroaryl having 4 to40, preferably 4 to 20 ring atoms, and straight-chain or branched alkyl,alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in whichone or more H atoms may optionally be replaced by F or Cl.

“Substituted silyl or aryl” preferably means substituted by halogen,—CN, R^(y), —OR^(y), —CO—R^(y), —CO—O—R^(y), —O—CO—R^(y) or—O—CO—O—R^(y), in which R^(y) denotes H, a straight-chain, branched orcyclic alkyl chain having 1 to 12 C atoms.

In the formula shown above and below, a substituted phenylene ring

is preferably

in which L has, on each occurrence identically or differently, one ofthe meanings given above and below, and is preferably F, Cl, CN, NO₂,CH₃, C₂H₅, C(CH₃)₃, CH(CH₃)₂, CH₂CH(CH₃)C₂H₅, OCH₃, OC₂H₅, COCH₃,COC₂H₅, COOCH₃, COOC₂H₅, CF₃, OCF₃, OCHF₂, OC₂F₅ or P-Sp-, verypreferably F, Cl, CN, CH₃, C₂H₅, OCH₃, COCH₃, OCF₃ or P-Sp-, mostpreferably F, Cl, CH₃, OCH₃, COCH₃ or OCF₃.

“Halogen” denotes F, Cl, Br or I, preferably F or Cl, more preferably F.

“Polymerisable groups” (P) are preferably selected from groupscontaining a C═C double bond or C≡C triple bond, and groups which aresuitable for polymerisation with ring opening, such as, for example,oxetane or epoxide groups.

Preferably, polymerisable groups (P) are selected from the groupconsisting of CH₂═CW¹—COO—, CH₂═CW¹—CO—,

CH₂═CW²—(O)_(k3)—, CW¹═CH—CO—(O)_(k3)—, CW¹═CH—CO—NH—, CH₂═CW¹—CO—NH—,CH₃—CH═CH—O—, (CH₂═CH)₂CH—OCO—, (CH₂═CH—CH₂)₂CH—OCO—, (CH₂═CH)₂CH—O—,(CH₂═CH—CH₂)₂N—, (CH₂═CH—CH₂)₂N—CO—, CH₂═CW¹—CO—NH—,CH₂═CH—(COO)_(k1)-Phe-(O)_(k2)—, CH₂═CH—(CO)_(k1)-Phe-(O)_(k2)—,Phe-CH═CH—,in whichW¹ denotes H, F, Cl, CN, CF₃, phenyl or alkyl having 1 to 5 C atoms, inparticular H, F, Cl or CH₃,W² denotes H or alkyl having 1 to 5 C atoms, in particular H, methyl,ethyl or n-propyl,W³ and W⁴ each, independently of one another, denote H, Cl or alkylhaving 1 to 5 C atoms, Phe denotes 1,4-phenylene, which is optionallysubstituted by one or more radicals L as being defined above but beingdifferent from P-Sp, preferably preferred substituents L are F, Cl, CN,NO₂, CH₃, C₂H₅, OCH₃, OC₂H₅, COCH₃, COC₂H₅, COOCH₃, COOC₂H₅, CF₃, OCF₃,OCHF₂, OC₂F₅, furthermore phenyl, andk₁, k₂ and k₃ each, independently of one another, denote 0 or 1, k₃preferably denotes 1, and k₄ is an integer from 1 to 10.

Particularly preferred polymerizable groups P are CH₂═CH—COO—,CH₂═C(CH₃)—COO—, CH₂═CF—COO—, CH₂═CH—, CH₂═CH—O—, (CH₂═CH)₂CH—OCO—,(CH₂═CH)₂CH—O—,

in which W² denotes H or alkyl having 1 to 5 C atoms, in particular H,methyl, ethyl or n-propyl,

Further preferred polymerizable groups (P) are vinyloxy, acrylate,methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, mostpreferably acrylate or methacrylate, in particular acrylate.

Preferably, all multireactive polymerisable compounds and sub-formulaethereof contain instead of one or more radicals P-Sp-, one or morebranched radicals containing two or more polymerisable groups P(multireactive polymerisable radicals).

Suitable radicals of this type, and polymerisable compounds containingthem, are described, for example, in U.S. Pat. No. 7,060,200 B1 or US2006/0172090 A1.

Particular preference is given to multireactive polymerisable radicalsselected from the following formulae:

—X-alkyl-CHP^(x)—CH₂—CH₂P^(y)  I*a

—X-alkyl-C(CH₂P^(x))(CH₂P^(y))—CH₂P^(z)  I*b

—X-alkyl-CHP^(x)CHP^(y)—CH₂P^(z)  I*c

—X-alkyl-C(CH₂P^(x))(CH₂P^(y))—C_(aa)H_(2aa+1)  I*d

—X-alkyl-CHP^(x)—CH₂P^(y)  I*e

—X-alkyl-CHP^(x)P^(y)  I*f

—X-alkyl-CP^(x)P^(y)—C_(aa)H_(2aa+1)  I*g

—X-alkyl-C(CH₂P^(v))(CH₂P^(w))—CH₂OCH₂—C(CH₂P^(x))(CH₂P^(y))CH₂P^(z)  I*h

—X-alkyl-CH((CH₂)_(aa)P^(x))((CH₂)_(bb)P^(y))  I*i

—X-alkyl-CHP^(x)CHP^(y)—C_(aa)H_(2aa+1)  I*k

in which

-   alkyl denotes a single bond or straight-chain or branched alkylene    having 1 to 12 C atoms, in which one or more non-adjacent CH₂ groups    may each be replaced, independently of one another, by    —C(R^(x))═C(R^(x))—, —C≡C—, —N(R^(x))—, —O—, —S—, —CO—, —CO—O—,    —O—CO—, —O—CO—O— in such a way that O and/or S atoms are not linked    directly to one another, and in which, in addition, one or more H    atoms may be replaced by F, Cl or CN, where R^(x) has one the    above-mentioned meaning,-   _(aa) and _(bb) each, independently of one another, denote 0, 1, 2,    3, 4, 5 or 6,-   X has one of the meanings indicated for X′, and-   P^(v) to P^(z) each, independently of one another, have one of the    meanings indicated above for P.

Preferred spacer groups Sp are selected from the formula Sp′-X′, so thatthe radical “P-Sp-” conforms to the formula “P-Sp′-X′—”, where

-   Sp′ denotes alkylene having 1 to 20, preferably 1 to 12 C atoms,    which is optionally mono- or polysubstituted by F, Cl, Br, I or CN    and in which, in addition, one or more non-adjacent CH₂ groups may    each be replaced, independently of one another, by —O—, —S—, —NH—,    —NR^(xx)—, —SiR^(xx)R^(yy)—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—,    —CO—S—, —NR^(xx)—CO—O—, —O—CO—NR^(0xx)—, —NR^(xx)—CO—NR^(yy)—,    —CH═CH— or —C≡C— in such a way that O and/or S atoms are not linked    directly to one another,-   X′ denotes —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR^(xx)—,    —NR^(xx)—CO—, —NR^(xx)—CO—NR^(yy)—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—,    —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—,    —CH═N—, —N═CH—, —N═N—, —CH═CR^(xx)—, —CY^(xx)═CY^(xx)—, —C≡C—,    —CH═CH—COO—, —OCO—CH═CH— or a single bond,-   R^(xx) and R^(yy) each, independently of one another, denote H or    alkyl having 1 to 12 C atoms, and-   Y^(xx) and Y^(yy) each, independently of one another, denote H, F,    Cl or CN.-   X′ is preferably —O—, —S— —CO—, —COO—, —OCO—, —O—COO—, —CO—NR^(xx)—,    —NR^(xx)—CO—, —NR^(xx)—CO—NR^(yy)— or a single bond.

Typical spacer groups Sp′ are, for example, —(CH₂)_(p1)—,—(CH₂CH₂O)_(q1)—CH₂CH₂—, —CH₂CH₂—S—CH₂CH₂—, —CH₂CH₂—NH—CH₂CH₂— or—(SiR^(xx)R^(yy)—O)_(p1)—, in which p1 is an integer from 1 to 12, q1 isan integer from 1 to 3, and R^(xx) and R^(yy) have the above-mentionedmeanings.

Particularly preferred groups —X′-Sp′- are —(CH₂)_(p1)—, —O—(CH₂)_(p1)—,—OCO—(CH₂)_(p1)—, —OCOO—(CH₂)_(p1)—, in which p1 is an integer from 1 to12.

Particularly preferred groups Sp′ are, for example, in each casestraight-chain, methylene, ethylene, propylene, butylene, pentylene,hexylene, heptylene, octylene, nonylene, decylene, undecylene,dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene,ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene,ethenylene, propenylene and butenylene.

For the present invention,

denote trans-1,4-cyclohexylene,

denote 1,4-phenylene.

For the present invention the groups —COO— or —CO₂— denote an estergroup of formula

and the groups —OCO—, —O₂C— or —OOC— denote an ester group of formula

A “polymer network” is a network in which all polymer chains areinterconnected to form a single macroscopic entity by many crosslinks.

The polymer network can occur in the following types:

-   -   A graft polymer molecule is a branched polymer molecule in which        one or more the side chains are different, structurally or        configurationally, from the main chain.    -   A star polymer molecule is a branched polymer molecule in which        a single branch point gives rise to multiple linear chains or        arms. If the arms are identical, the star polymer molecule is        said to be regular. If adjacent arms are composed of different        repeating subunits, the star polymer molecule is said to be        variegated.    -   A comb polymer molecule consists of a main chain with two or        more three-way branch points and linear side chains. If the arms        are identical the comb polymer molecule is said to be regular.    -   A brush polymer molecule consists of a main chain with linear,        unbranched side chains and where one or more of the branch        points has four-way functionality or larger.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components. On the otherhand, the word “comprise” also encompasses the term “consisting of” butis not limited to it.

Throughout the description and claims of this specification, the words“obtainable” and “obtained” and variations of the words, mean “includingbut not limited to”, and are not intended to (and do not) exclude othercomponents. On the other hand, the word “obtainable” also encompassesthe term “obtained” but is not limited to it.

All concentrations are quoted in percent by weight and relate to therespective mixture as a whole, all temperatures are quoted in degreesCelsius and all temperature differences are quoted in differentialdegrees.

DETAILED DESCRIPTION

Preferred compounds of formula TRI are selected from the followingsubformulae TRI-1:

wherein R² to R⁹ and R^(a) have one of the meanings as given underformula TRI.

In a preferred embodiment R² to R⁹ each denote H in formula TRI-1 andR^(a) denotes in formula TRI-1 a radical —(CH₂)_(n)—Y₁—X₁,

wherein

-   Y₁ represent a single bond —COO—, —OCO—, -L₁-, —O-L₁O—, —OL₁-,    -L₁OCO—, -L₁COO—, —CO—CH═CH—, —CH═CH—CO—, —CH═CH—COO—, —CH═CH—OCO—,    or —COO—CH═CH—,-   L₁ denotes an optionally branched alkylene group having 1 to 8    carbon atoms;-   m denotes an integer between 0 to 8, and-   X₁ denotes a straight chain or branched alkyl having 1 to 12,    preferably 1 to 8 C atoms, which is optionally mono- or    polysubstituted by F, Cl, Br, I or CN and in which, in addition, one    or more non-adjacent CH₂ groups may each be replaced, independently    of one another, by —O—, —S—, —NH—, —NR^(xx)—, —SiR^(xx)R^(yy)—,    —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —NR^(xx)—CO—O—,    —O—CO—NR^(xx)—, —NR^(xx)—CO—NR^(yy)—, —CH═CH— or —C≡C— in such a way    that O and/or S atoms are not linked directly to one another.

An especially preferred compound of formula TRI-1 is the followingcompound:

Further preferred compounds of formula TRI are selected from thefollowing subformula TRI-2:

wherein R² to R⁹ and R^(a) have one of the meanings as given underformula TRI or TRI-1.

Further preferred compounds of formula TRI are selected from thefollowing subformula TRI-3:

wherein R² to R⁹ and R^(a) have one of the meanings as given underformula TRI or TRI-1.

Further preferred compounds of formula TRI are selected from thefollowing subformula TRI-4:

wherein R², R⁵, R⁶, R⁸ and R⁹ and R^(a) have one of the meanings asgiven under formula TRI or TRI-1.

Further preferred compounds of formula TRI are selected from thefollowing subformula TRI-5:

wherein R², R⁶, and R⁹ have one of the meanings as given under formulaTRI or TRI-1 and R^(a), R_(b), and R_(c) denotes have each andindependently one of the meanings as given for R_(a) under formula TRIor TRI-1.

Further preferred compounds of formula TRI are selected from thefollowing subformula TRI-6:

wherein R², R⁶, and R⁹ have one of the meanings as given under formulaTRI or TRI-1 andwherein

-   Y₁, Y₂ and Y₃ each and independently from another denote a single    bond —COO—, —OCO—, -L₁-, —O-L₁O—, —OL₁-, -L₁OCO—, -L₁COO—,    —CO—CH═CH—, —CH═CH—CO—, —CH═CH—COO—, —CH═CH—OCO—, or —COO—CH═CH—,-   L₁ denotes each and independently from another in each occurrence an    optionally branched alkylene group having 1 to 8 carbon atoms;-   m, n and o each and independently from another denotes an integer    between 0 to 8, and-   X₁, X₂ and X₃ each and independently from another denotes a straight    chain or branched alkyl having 1 to 12, preferably 1 to 8 C atoms,    which is optionally mono- or polysubstituted by F, Cl, Br, I or CN    and in which, in addition, one or more non-adjacent CH₂ groups may    each be replaced, independently of one another, by —O—, —S—, —NH—,    —NR^(xx)—, —SiR^(xx)R^(yy)—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—,    —CO—S—, —NR^(xx)—CO—O—, —O—CO—NR^(xx)—, —NR^(xx)—CO—NR^(yy)—,    —CH═CH— or —C≡C— in such a way that O and/or S atoms are not linked    directly to one another.

In a preferred embodiment R², R⁶, and R⁹ denote each methyl, ethyl,propyl, preferably each methyl.

In a further preferred embodiment Y₁, Y₂ and Y₃ are identical and denote—COO—, or —OCO—.

In a further preferred embodiment m, n and o are identical and denote aninteger between 1 to 4, preferably 2.

In a further preferred embodiment X₁, X₂ and X₃ are identical and eachdenote a straight chain or branched alkyl having 1 to 12, preferably 1to 8 C atoms.

Example for especially preferred compounds of formula TRI are given inthe following list,

Preferably the proportion of compounds of formula TRI in the LC mediumis from 0.01 to 5%, very preferably from 0.1 to 3%, in particular 0.5 to2%.

Preferably the proportion of compounds of formula TRI in the LC mediumis from 10 to 5000 ppm, very preferably from 100 to 3000 ppm, inparticular 500 to 2000 ppm.

The compound of formula TRI and subformulae thereof are preferablyutilized either alone in the LC medium or more preferably in combinationwith one or more compounds of formula S0 and/or S1, preferably with oneor more compounds of formula S1,

wherein the individual radicals, independently of each other and on eachoccurrence identically or differently, have the following meanings:

-   P^(a) is a polymerizable group, preferably a (meth)acrylate group,    Sp straight chain or branched alkylene having 1 to 12 C atoms,    where, in addition, one or two non-adjacent CH₂ groups may be    replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that 0    atoms are not linked directly to one another,-   X¹ and X² denote each and independently    -   —O—, —CH═CH—, —CF₂O—, —OCF₂—, —CH₂O—, —OCH₂—, —CO—O—, —O—CO—,        —C₂F₄—, —CF═CF— or a single bond, preferably —O—, —CO—O—,        —O—CO—,-   R^(a-d) denote each and independently straight chain or branched    alkyl with 1 to 20 C atoms, preferably with 1 to 15 C atoms, very    preferably with 1 to 12 C atoms,-   R¹ and R² denote each and independently H, CH₃, OH, OR^(a) or O..

Preferred compounds of formula S0 are selected from the followingsubformulae

wherein P^(a) is a polymerizable group.

Very preferred compounds of formula S0 are selected from the followingsubformulae

Preferred compounds of formula S1 are selected from the followingsubformulae

wherein n1 is an integer from 2 to 12 and wherein one or more H-atoms inthe radical (CH₂)_(n1) are optionally replaced by a methyl, ethyl,propyl, butyl, pentyl or hexyl group, and R¹¹ and R¹² denote each andindependently straight chain or branched alkyl with 1 to 20 C atoms.

Very preferred compounds of formula S1 are selected from the followingsubformulae

Preferably the proportion of compounds of formula S0 and/or S1 or itssubformulae in the LC medium is from 0.01 to 1%, very preferably from0.05 to 0.5%, in particular 0.07 to 0.1%.

Preferably the proportion of compounds of formula S0 and/or S1 or itssubformulae in the LC medium is from 10 to 2000 ppm, very preferablyfrom 50 to 1500 ppm, in particular 100 to 1000 ppm.

The combination of compounds of formula TRI and S0 and/or S1 leads topolymerizable LC media having a further reliability in terms of UV lightstress.

Preferably, one or more di- or multireactive mesogenic compounds areselected of formula DRM

P¹-Sp¹-MG-Sp²-P²  DRM

whereinP¹ and P² independently of each other denote a polymerisable group,Sp¹ and Sp² independently of each other are a spacer group or a singlebond, andMG is a rod-shaped mesogenic group, which is preferably selected offormula MG

-(A¹-Z¹)_(n)-A²-  MG

whereinA¹ and A² denote, in case of multiple occurrence independently of oneanother, an aromatic or alicyclic group, which optionally contains oneor more heteroatoms selected from N, O and S, and is optionally mono- orpolysubstituted by L¹,L¹ is P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,—C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)OR⁰⁰, —C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅, optionallysubstituted silyl, aryl or heteroaryl with 1 to 12, preferably 1 to 6 Catoms, and straight chain or branched alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12,preferably 1 to 6 C atoms, wherein one or more H atoms are optionallyreplaced by F or Cl,R⁰⁰ and R⁰⁰⁰ independently of each other denote H or alkyl with 1 to 12C-atoms,z¹ denotes, in case of multiple occurrence independently of one another,—O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—, —CO—NR⁰⁰—,—NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰, —NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—, —OCH₂—, —CH₂O—,—SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)_(n1),—CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰⁰—,—CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond,Y¹ and Y² independently of each other denote H, F, C or CN,n is 1, 2, 3 or 4, preferably 1 or 2, most preferably 2,n1 is an integer from 1 to 10, preferably 1, 2, 3 or 4.

Preferred groups A¹ and A² include, without limitation, furan, pyrrol,thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene,cyclohexylene, bicyclooctylene, cyclohexenylene, pyridine, pyrimidine,pyrazine, azulene, indane, fluorene, naphthalene, tetrahydronaphthalene,anthracene, phenanthrene and dithienothiophene, all of which areunsubstituted or substituted by 1, 2, 3 or 4 groups L as defined above.

Particular preferred groups A¹ and A² are selected from 1,4-phenylene,pyridine-2,5-diyl, pyrimidine-2,5-diyl, thiophene-2,5-diyl,naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl,indane-2,5-diyl, bicyclooctylene or 1,4-cyclohexylene wherein one or twonon-adjacent CH₂ groups are optionally replaced by O and/or S, whereinthese groups are unsubstituted or substituted by 1, 2, 3 or 4 groups Las defined above.

Particular preferred groups Z¹ are in each occurrence independently fromanother preferably selected from —COO—, —OCO—, —CH₂CH₂—, —CF₂O—, —OCF₂—,—C≡C—, —CH═CH—, —OCO—CH═CH—, —CH═CH—COO—, or a single bond,

Very preferred direactive mesogenic compounds of formula DRM areselected from the following formulae:

wherein

-   P⁰ is, in case of multiple occurrence independently of one another,    a polymerisable group, preferably an acryl, methacryl, oxetane,    epoxy, vinyl, heptadiene, vinyloxy, propenyl ether or styrene group,-   L has on each occurrence identically or differently one of the    meanings given for L¹ in formula DRM, and is preferably, in case of    multiple occurrence independently of one another, selected from F,    Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl,    alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C    atoms,-   r is 0, 1, 2, 3 or 4,-   x and y are independently of each other 0 or identical or different    integers from 1 to 12,-   z is each and independently, 0 or 1, with z being 0 if the adjacent    x or y is 0.

Especially preferred are compounds of formula DRMa1, DRMa2 and DRMa3, inparticular those of formula DRMa1.

Preferably, the polymerisable LC material additionally comprises atleast one monoreactive mesogenic compound, which is preferably selectedfrom formula MRM,

P¹-Sp¹-MG-R  MRM

wherein P¹, Sp¹ and MG have the meanings given in formula DRM,

-   R F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR^(x)R^(y), —C(═O)X, —C(═O)OR^(x), —C(═O)R^(y), —NR^(x)R^(y),    —OH, —SF₅, optionally substituted silyl, straight chain or branched    alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 C atoms, wherein    one or more H atoms are optionally replaced by F or Cl,-   X is halogen, preferably F or Cl, and-   R^(x) and R^(y) are independently of each other H or alkyl with 1 to    12 C-atoms.

Preferably, the monoreactive mesogenic compounds of formula MRM areselected from the following formulae.

wherein P⁰, L, r, x, y and z are as defined in formula DRMa-1 to formulaDRMe,

-   R⁰ is alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl,    alkylcarbonyloxy or alkoxycarbonyloxy with 1 or more, preferably 1    to 15 C atoms or denotes Y⁰,-   Y⁰ is F, Cl, CN, NO₂, OCH₃, OCN, SCN, SF₅, or mono- oligo- or    polyfluorinated alkyl or alkoxy with 1 to 4 C atoms,-   Z⁰ is —COO—, —OCO—, —CH₂CH₂—, —CF₂O—, —OCF₂—, —CH═CH—, —OCO—CH═CH—,    —CH═CH—COO—, or a single bond,-   A⁰ is, in case of multiple occurrence independently of one another,    1,4-phenylene that is unsubstituted or substituted with 1, 2, 3 or 4    groups L, or trans-1,4-cyclohexylene,-   u and v are independently of each other 0, 1 or 2,-   w is 0 or 1,    and wherein the benzene and naphthalene rings can additionally be    substituted with one or more identical or different groups L.

Further preferred are compounds of formula MRM1, MRM2, MRM3, MRM4, MRM5,MRM6, MRM7, MRM9 and MRM10, especially those of formula MRM1, MRM4,MRM6, and MRM7, and in particular those of formulae MRM1 and MRM7.

The compounds of the formulae DRM, MRM, and sub-formulae thereof can bepre-pared analogously to processes known to the person skilled in theart and described in standard works of organic chemistry, such as, forexample, in Houben-Weyl, Methoden der organischen Chemie [Methods ofOrganic Chemistry], Thieme-Verlag, Stuttgart.

The proportion of said mono-, di- or multireactive liquid-crystallinecompounds in a polymerisable liquid-crystalline material according tothe present invention as a whole, is preferably in the range from 30 to99.9% by weight, more preferably in the range from 40 to 99.9% by weightand even more preferably in the range from 50 to 99.9% by weight.

In a preferred embodiment, the proportion of the di- or multireactivepolymerisable mesogenic compounds in a polymerisable liquid-crystallinematerial according to the present invention as a whole, is preferably inthe range from 5 to 99% by weight, more preferably in the range from 10to 97% by weight and even more preferably in the range from 15 to 95% byweight.

In another preferred embodiment, the proportion of the monoreactivepolymerisable mesogenic compounds in a polymerisable liquid-crystallinematerial according to the present invention as a whole, is, if present,preferably in the range from 5 to 80% by weight, more preferably in therange from 10 to 75% by weight and even more preferably in the rangefrom 15 to 70% by weight.

In another preferred embodiment, the proportion of the multireactivepolymerizable mesogenic compounds in a polymerisable liquid-crystallinematerial according to the present invention as a whole is, if present,preferably in the range from 1 to 30% by weight, more preferably in therange from 2 to 20% by weight and even more preferably in the range from3 to 10% by weight.

In another preferred embodiment the polymerisable LC material does notcontain polymerizable mesogenic compounds having more than twopolymerisable groups.

In another preferred embodiment the polymerisable LC material does notcontain polymerizable mesogenic compounds having less than twopolymerisable groups.

In another preferred embodiment the polymerisable LC material is anachiral material, i.e. it does not contain any chiral polymerizablemesogenic compounds or other chiral compounds.

In a further preferred embodiment, the polymerisable LC materialcomprises at least one monoreactive mesogenic compound, preferablyselected from formulae MRM-1, at least one direactive mesogeniccompound, preferably selected from formula DRMa-1, and one or morecompounds of formula TRI.

In a further preferred embodiment, the polymerisable LC materialcomprises at least one monoreactive mesogenic compound, preferablyselected from formula MRM-7, at least one direactive mesogenic compound,preferably selected from formula DRMa-1, and one or more compounds offormula TRI.

In a further preferred embodiment, the polymerisable LC materialcomprises at least two monoreactive mesogenic compound, preferablyselected from compounds of formulae MRM-1 and/or MRM-7, at least onedireactive mesogenic compound, preferably selected from formula DRMa-1,and one or more compounds of formula TRI.

In a further preferred embodiment, the polymerisable LC materialcomprises at least two monoreactive mesogenic compounds, preferablyselected from compounds of formulae MRM-1 and/or MRM-7, at least twodireactive mesogenic compounds, preferably selected from compounds offormula DRMa-1, and one or more compounds of formula TRI.

In a further preferred embodiment, the polymerisable LC materialcomprises at least two direactive mesogenic compounds, preferablyselected from compounds of formula DRMa-1, and one or more compounds offormula TRI.

In a further preferred embodiment, especially for negative opticaldispersion applications, the polymerisable LC material as describedabove comprises additionally one or more compounds of formula ND,

wherein

-   U^(1,2) are independently of each other selected from

-   -   including their mirror images, wherein the rings U¹ and U² are        each bonded to the group —(B)_(q)— via the axial bond, and one        or two non-adjacent CH₂ groups in these rings are optionally        replaced by O and/or S, and the rings U¹ and U² are optionally        substituted by one or more groups L,

-   Q^(1,2) are independently of each other CH or SiH,

-   Q³ is C or Si,

-   B is in each occurrence independently of one another —C≡C—,    —CY¹═CY²— or an optionally substituted aromatic or heteroaromatic    group,

-   Y^(1,2) are independently of each other H, F, Cl, CN or R⁰,

-   q is an integer from 1 to 10, preferably 1, 2, 3, 4, 5, 6 or 7,

-   A¹⁻⁴ are independently of each other selected from non-aromatic,    aromatic or heteroaromatic carbocyclic or heterocyclic groups, which    are optionally substituted by one or more groups R⁵, and wherein    each of -(A¹-Z¹)_(m)—U¹—(Z²-A²)_(n)- and    -(A³-Z³)_(o)—U²—(Z⁴-A⁴)_(p)- does not contain more aromatic groups    than non-aromatic groups and preferably does not contain more than    one aromatic group,

-   Z¹-4 are independently of each other —O—, —S—, —CO—, —COO—, —OCO—,    —O—COO—, —CO—NR⁰—, —NR⁰—CO—, —NR⁰—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—,    —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)₃—,    —(CH₂)₄—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═CH—, —CY¹═CY²—, —CH═N—,    —N═CH—, —N═N—, —CH═CR⁰—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR⁰R⁰⁰ or    a single bond,

-   R⁰ and R⁰⁰ are independently of each other H or alkyl with 1 to 12    C-atoms,

-   m and n are independently of each other 0, 1, 2, 3 or 4,

-   and p are independently of each other 0, 1, 2, 3 or 4,

-   R¹⁻⁵ are independently of each other identical or different groups    selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H,    —SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, P-Sp-, optionally substituted silyl,    or carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally    substituted and optionally comprises one or more hetero atoms, or    denote P or P-Sp-, or are substituted by P or P-Sp-, wherein the    compounds comprise at least one group R¹⁻⁵ denoting or being    substituted by P or P-Sp-,

-   P is a polymerisable group,

-   Sp is a spacer group or a single bond.

Preferably, the subgroups forming the bridging group B in formula ND arepreferably selected from groups having a bonding angle of 120° or more,preferably in the range of 180°. Very preferred are —C≡C— groups ordivalent aromatic groups connected to their adjacent groups inpara-position, like e.g. 1,4-phenylene, naphthalene-2,6-diyl,indane-2,6-diyl or thieno[3,2-b]thiophene-2,5-diyl.

Further possible subgroups include —CH═CH—, —CY¹═CY²—, —CH═N—, —N═CH—,—N═N— and —CH═CR⁰— wherein Y¹, Y², R⁰ have the meanings given above.

Preferably the bridging group, or —(B)_(q)— in formula ND, comprises oneor more groups selected from the group consisting of —C≡C—, optionallysubstituted 1,4-phenylene and optionally substituted9H-fluorene-2,7-diyl. The subgroups, or B in formula ND, are preferablyselected from the group consisting of —C≡C—, optionally substituted1,4-phenylene and optionally substituted 9H-fluorene-2,7-diyl, whereinin the fluorene group the H-atom in 9-position is optionally replaced bya carbyl or hydrocarbyl group.

Very preferably the bridging group, or —(B)_(q)— in formula ND, areselected from —C≡C—, —C≡C—C≡C—, —C≡C—C≡C—C≡C—, —C≡C—C≡C—C≡C—C≡C—,

wherein r is 0, 1, 2, 3 or 4 and L has the meaning as described below.

Preferably, the non-aromatic rings of the mesogenic groups where thebridging group is attached, like U¹ and U² in formula ND, are preferablyselected from

wherein R⁵ is as defined in formula ND.

Preferably, the aromatic groups A¹⁻⁴ in formula ND, may be mononuclear,i.e. having only one aromatic ring (like for example phenyl orphenylene), or polynuclear, i.e. having two or more fused rings (likefor example napthyl or naphthylene). Especially preferred are mono-, bi-or tricyclic aromatic or heteroaromatic groups with up to 25 C atomsthat may also comprise fused rings and that are optionally substituted.

Preferably, the non-aromatic carbocyclic and heterocyclic rings A¹⁻⁴ inthe compounds of formula ND, include those which are saturated (alsoreferred to as “fully saturated”), i.e. they do only contain C-atoms orhetero atoms connected by single bonds, and those which are unsaturated(also referred to as “partially saturated”), i.e. they also compriseC-atoms or hetero atoms connected by double bonds. The non-aromaticrings may also comprise one or more hetero atoms, preferably selectedfrom Si, O, N and S.

Preferably the non-aromatic and aromatic rings, or A¹⁻⁴ in formula ND,are selected from trans-1,4-cyclohexylene and 1,4-phenylene that isoptionally substituted with one or more groups L.

Very preferred are compounds of formula ND, wherein m and p are 1 and nand o are 1 or 2. Further preferred are compounds of formula ND, whereinm and p are 1 or 2 and n and o are 0. Further preferred are compoundswherein m, n, o and p are 2.

In the compounds of formula ND, the linkage groups connecting thearomatic and non-aromatic cyclic groups in the mesogenic groups, orZ¹⁻⁴, are preferably selected from —O—, —S—, —CO—, —COO—, —OCO—,—O—COO—, —CO—NR⁰—, —NR⁰—CO—, —NR⁰—CO—NR⁰—, —OCH₂—, —CH₂O—, —SCH₂—,—CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)₃—, —(CH₂)₄—,—CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═CH—, —CY¹═CY²—, —CH═N—, —N═CH—, —N═N—,—CH═CR⁰—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR⁰R⁰⁰ or a single bond, verypreferably from —COO—, —OCO— and a single bond.

Preferably, in the compounds of formula ND, the substituents on therings, such as L, are preferably selected from P-Sp-, F, Cl, Br, I, —CN,—NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR⁰R⁰⁰, —C(═O)X, —C(═O)OR⁰,—C(═O)R⁰, —NR⁰R⁰⁰, —OH, —SF₅, optionally substituted silyl, aryl orheteroaryl with 1 to 12, preferably 1 to 6 C atoms, and straight chainor branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,wherein R⁰ and R⁰⁰ are as defined in formula ND and X is halogen.

Preferably, the compounds of formula ND comprise one or more terminalgroups, like R¹⁻⁴, or substituents, like R⁵, that are substituted by twoor more polymerisable groups P or P-Sp- (multifunctional polymerisablegroups). Suitable multifunctional polymerisable groups of this type aredisclosed for example in U.S. Pat. No. 7,060,200 B1 or US 2006/0172090A1.

Very preferred compounds of formula ND are those of the following subformulae:

wherein R¹⁻⁵, A¹⁻⁴, Z¹⁻⁴, B, m, n, o, p and q have one the meaningsgiven above.

Especially preferred are compounds of the following sub formulae:

wherein Z has one of the meanings of Z¹ given above, R has one of themeanings of R¹ as given above that is different from P-Sp-, and P, Sp, Land r are as defined above, and the benzene rings in the mesogenicgroups are optionally substituted by one or more groups L as definedabove.

Preference is furthermore given to a polymerisable liquid crystallinemedium wherein the compounds of formula ND are selected from the groupof compounds of formula ND 25 or ND 26, in particular wherein Z denotes—COO—, r is in each occurrence 0, and P, Sp are as defined above.

P-Sp- in these preferred compounds is preferably P-Sp′-X′, with X′preferably being —O—, —COO— or —OCOO—.

The compounds of formula ND, its subformulae and suitable methods fortheir synthesis are disclosed in WO 2008/119427 A1.

The amount of compounds of formula ND in the polymerisable LC materialis preferably from 1 to 50%, very preferably from 1 to 40%.

Especially the combination of compound or formula TRI with compounds offormula ND leads to a beneficial decrease of the optical dispersion incomparison to polymerisable LC materials utilizing not that specificcombination.

In a further preferred embodiment the polymerisable LC materialoptionally comprises one or more additives selected from the groupconsisting of further polymerisation initiators, antioxidants,surfactants, stabilisers, catalysts, sensitizers, inhibitors,chain-transfer agents, co-reacting monomers, reactive thinners,surface-active compounds, lubricating agents, wetting agents, dispersingagents, hydrophobing agents, adhesive agents, flow improvers, degassingor defoaming agents, deaerators, diluents, reactive diluents,auxiliaries, colourants, dyes, pigments and nanoparticles.

In another preferred embodiment, the polymerisable LC materialoptionally comprises one or more additives selected from polymerisablenon-mesogenic compounds (reactive thinners). The amount of theseadditives in the polymerisable LC material is preferably from 0 to 30%,very preferably from 0 to 25%.

The reactive thinners used are not only substances which are referred toin the actual sense as reactive thinners, but also auxiliary compoundsalready mentioned above which contain one or more complementary reactiveunits or polymerizable groups P, for example hydroxyl, thiol-, or aminogroups, via which a reaction with the polymerisable units of theliquid-crystalline compounds can take place.

The substances, which are usually capable of photopolymerisation,include, for example, mono-, bi- and polyfunctional compounds containingat least one olefinic double bond. Examples thereof are vinyl esters ofcarboxylic acids, for example of lauric, myristic, palmitic and stearicacid, and of dicarboxylic acids, for example of succinic acid, adipicacid, allyl and vinyl ethers and methacrylic and acrylic esters ofmonofunctional alcohols, for example of lauryl, myristyl, palmityl andstearyl alcohol, and diallyl and divinyl ethers of bifunctionalalcohols, for example ethylene glycol and 1,4-butanediol.

Also suitable are, for example, methacrylic and acrylic esters ofpolyfunctional alcohols, in particular those which contain no furtherfunctional groups, or at most ether groups, besides the hydroxyl groups.Examples of such alcohols are bifunctional alcohols, such as ethyleneglycol, propylene glycol and their more highly condensedrepresentatives, for example diethylene glycol, triethylene glycol,dipropylene glycol, tripropylene glycol etc., butanediol, pentanediol,hexanediol, neopentyl glycol, alkoxylated phenolic compounds, such asethoxylated and propoxylated bisphenols, cyclohexanedimethanol,trifunctional and polyfunctional alcohols, such as glycerol,trimethylolpropane, butanetriol, trimethylolethane, pentaerythritol,ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, and thecorresponding alkoxylated, in particular ethoxylated and propoxylatedalcohols.

Other suitable reactive thinners are polyester (meth)acrylates, whichare the (meth)acrylic ester of polyesterols.

Examples of suitable polyesterols are those which can be prepared byesterification of polycarboxylic acids, preferably dicarboxylic acids,using polyols, preferably diols. The starting materials for suchhydroxyl-containing polyesters are known to the person skilled in theart. Dicarboxylic acids which can be employed are succinic, glutaricacid, adipic acid, sebacic acid, o-phthalic acid and isomers andhydrogenation products thereof, and esterifiable and transesterifiablederivatives of said acids, for example anhydrides and dialkyl esters.Suitable polyols are the abovementioned alcohols, preferablyethyleneglycol, 1,2- and 1,3-propylene glycol, 1,4-butanediol,1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol and polyglycolsof the ethylene glycol and propylene glycol type.

Suitable reactive thinners are furthermore 1,4-divinylbenzene, triallylcyanurate, acrylic esters of tricyclodecenyl alcohol of the followingformula

also known under the name dihydrodicyclopentadienyl acrylate, and theallyl esters of acrylic acid, methacrylic acid and cyanoacrylic acid.

Of the reactive thinners, which are mentioned by way of example, thosecontaining photopolymerizable groups are used in particular and in viewof the abovementioned preferred compositions.

This group includes, for example, dihydric and polyhydric alcohols, forexample ethylene glycol, propylene glycol and more highly condensedrepresentatives thereof, for example diethylene glycol, triethyleneglycol, dipropylene glycol, tripropylene glycol etc., butanediol,pentanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol,glycerol, trimethylolpropane, butanetriol, trimethylolethane,pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol,mannitol and the corresponding alkoxylated, in particular ethoxylatedand propoxylated alcohols.

The group furthermore also includes, for example, alkoxylated phenoliccompounds, for example ethoxylated and propoxylated bisphenols.

These reactive thinners may furthermore be, for example, epoxide orurethane (meth)acrylates.

Epoxide (meth)acrylates are, for example, those as obtainable by thereaction, known to the person skilled in the art, of epoxidized olefinsor poly- or diglycidyl ether, such as bisphenol A diglycidyl ether, with(meth)acrylic acid.

Urethane (meth)acrylates are, in particular, the products of a reaction,likewise known to the person skilled in the art, of hydroxylalkyl(meth)acrylates with poly- or diisocyanates.

Such epoxide and urethane (meth)acrylates are included amongst thecompounds listed above as “mixed forms”.

If reactive thinners are used, their amount and properties must bematched to the respective conditions in such a way that, on the onehand, a satisfactory desired effect, for example the desired colour ofthe composition according to the invention, is achieved, but, on theother hand, the phase behaviour of the liquid-crystalline composition isnot excessively impaired. The low-crosslinking (high-crosslinking)liquid-crystalline compositions can be prepared, for example, usingcorresponding reactive thinners, which have a relatively low (high)number of reactive units per molecule.

The group of diluents include, for example:

C1-C4-alcohols, for example methanol, ethanol, n-propanol, isopropanol,butanol, isobutanol, sec-butanol and, in particular, the C5-C12-alcoholsn-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol,n-undecanol and n-dodecanol, and isomers thereof, glycols, for example1,2-ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-, 2,3- and1,4-butylene glycol, di- and triethylene glycol and di- and tripropyleneglycol, ethers, for example methyl tert-butyl ether, 1,2-ethylene glycolmono- and dimethyl ether, 1,2-ethylene glycol mono- and -diethylether,3-methoxypropanol, 3-isopropoxypropanol, tetrahydrofuran and dioxane,ketones, for example acetone, methyl ethyl ketone, methyl isobutylketone and diacetone alcohol (4-hydroxy-4-methyl-2-pentanone),C1-C5-alkyl esters, for example methyl acetate, ethyl acetate, propylacetate, butyl acetate and amyl acetate, aliphatic and aromatichydrocarbons, for example pentane, hexane, heptane, octane, isooctane,petroleum ether, toluene, xylene, ethylbenzene, tetralin, decalin,dimethylnaphthalene, white spirit, Shellsol® and Solvesso® mineral oils,for example gasoline, kerosine, diesel oil and heating oil, but alsonatural oils, for example olive oil, soya oil, rapeseed oil, linseed oiland sunflower oil.

It is of course also possible to use mixtures of these diluents in thecompositions according to the invention.

So long as there is at least partial miscibility, these diluents canalso be mixed with water. Examples of suitable diluents here areC1-C4-alcohols, for example methanol, ethanol, n-propanol, isopropanol,butanol, isobutanol and sec-butanol, glycols, for example 1,2-ethyleneglycol, 1,2- and 1,3-propylene glycol, 1,2-, 2,3- and 1,4-butyleneglycol, di- and triethylene glycol, and di- and tripropylene glycol,ethers, for example tetrahydrofuran and dioxane, ketones, for exampleacetone, methyl ethyl ketone and diacetone alcohol(4-hydroxy-4-methyl-2-pentanone), and C1-C4-alkyl esters, for examplemethyl, ethyl, propyl and butyl acetate.

The diluents are optionally employed in a proportion of from about 0 to10.0% by weight, preferably from about 0 to 5.0% by weight, based on thetotal weight of the polymerisable LC material.

The antifoams and deaerators (c1)), lubricants and flow auxiliaries(c2)), thermally curing or radiation-curing auxiliaries (c3)), substratewetting auxiliaries (c4)), wetting and dispersion auxiliaries (c5)),hydrophobicizing agents (c6)), adhesion promoters (c7)) and auxiliariesfor promoting scratch resistance (c8)) cannot strictly be delimited fromone another in their action.

For example, lubricants and flow auxiliaries often also act as antifoamsand/or deaerators and/or as auxiliaries for improving scratchresistance. Radiation-curing auxiliaries can also act as lubricants andflow auxiliaries and/or deaerators and/or as substrate wettingauxiliaries. In individual cases, some of these auxiliaries can alsofulfil the function of an adhesion promoter (c8)).

Corresponding to the above-said, a certain additive can therefore beclassified in a number of the groups c1) to c8) described below.

The antifoams in group c1) include silicon-free and silicon-containingpolymers. The silicon-containing polymers are, for example, unmodifiedor modified polydialkylsiloxanes or branched copolymers, comb or blockcopolymers comprising polydialkylsiloxane and polyether units, thelatter being obtainable from ethylene oxide or propylene oxide.

The deaerators in group c1) include, for example, organic polymers, forexample polyethers and polyacrylates, dialkylpolysiloxanes, inparticular dimethylpolysiloxanes, organically modified polysiloxanes,for example arylalkyl-modified polysiloxanes, and fluorosilicones.

The action of the antifoams is essentially based on preventing foamformation or destroying foam that has already formed. Antifoamsessentially work by promoting coalescence of finely divided gas or airbubbles to give larger bubbles in the medium to be deaerated, forexample the compositions according to the invention, and thus accelerateescape of the gas (of the air). Since antifoams can frequently also beemployed as deaerators and vice versa, these additives have beenincluded together under group c1).

Such auxiliaries are, for example, commercially available from Tego asTEGO® Foamex 800, TEGO® Foamex 805, TEGO® Foamex 810, TEGO® Foamex 815,TEGO® Foamex 825, TEGO® Foamex 835, TEGO® Foamex 840, TEGO® Foamex 842,TEGO® Foamex 1435, TEGO® Foamex 1488, TEGO® Foamex 1495, TEGO® Foamex3062, TEGO® Foamex 7447, TEGO® Foamex 8020, Tego® Foamex N, TEGO® FoamexK 3, TEGO® Antifoam 2-18, TEGO® Antifoam 2-18, TEGO® Antifoam 2-57,TEGO® Antifoam 2-80, TEGO® Antifoam 2-82, TEGO® Antifoam 2-89, TEGO®Antifoam 2-92, TEGO® Antifoam 14, TEGO® Antifoam 28, TEGO® Antifoam 81,TEGO® Antifoam D 90, TEGO® Antifoam 93, TEGO® Antifoam 200, TEGO®Antifoam 201, TEGO® Antifoam 202, TEGO® Antifoam 793, TEGO® Antifoam1488, TEGO® Antifoam 3062, TEGOPREN® 5803, TEGOPREN® 5852, TEGOPREN®5863, TEGOPREN® 7008, TEGO® Antifoam 1-60, TEGO® Antifoam 1-62, TEGO®Antifoam 1-85, TEGO® Antifoam 2-67, TEGO® Antifoam WM 20, TEGO® Antifoam50, TEGO® Antifoam 105, TEGO® Antifoam 730, TEGO® Antifoam MR 1015,TEGO® Antifoam MR 1016, TEGO® Antifoam 1435, TEGO® Antifoam N, TEGO®Antifoam KS 6, TEGO® Antifoam KS 10, TEGO® Antifoam KS 53, TEGO®Antifoam KS 95, TEGO® Antifoam KS 100, TEGO® Antifoam KE 600, TEGO®Antifoam KS 911, TEGO® Antifoam MR 1000, TEGO® Antifoam KS 1100, Tego®Airex 900, Tego® Airex 910, Tego® Airex 931, Tego® Airex 935, Tego®Airex 936, Tego® Airex 960, Tego® Airex 970, Tego® Airex 980 and Tego®Airex 985 and from BYK as BYK®-011, BYK®-019, BYK®-020, BYK®-021,BYK®-022, BYK®-023, BYK®-024, BYK®-025, BYK®-027, BYK®-031, BYK®-032,BYK®-033, BYK®-034, BYK®-035, BYK®-036, BYK®-037, BYK®-045, BYK®-051,BYK®-052, BYK®-053, BYK®-055, BYK®-057, BYK®-065, BYK®-066, BYK®-070,BYK®-080, BYK®-088, BYK®-141 and BYK®-A 530.

The auxiliaries in group c1) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 2.0% byweight, based on the total weight of the polymerisable LC material.

In group c2), the lubricants and flow auxiliaries typically includesilicon-free, but also silicon-containing polymers, for examplepolyacrylates or modifiers, low-molecular-weight polydialkylsiloxanes.The modification consists in some of the alkyl groups having beenreplaced by a wide variety of organic radicals. These organic radicalsare, for example, polyethers, polyesters or even long-chain(fluorinated)alkyl radicals, the former being used the most frequently.

The polyether radicals in the correspondingly modified polysiloxanes areusually built up from ethylene oxide and/or propylene oxide units.Generally, the higher the proportion of these alkylene oxide units inthe modified polysiloxane, the more hydrophilic is the resultantproduct.

Such auxiliaries are, for example, commercially available from Tego asTEGO® Glide 100, TEGO® Glide ZG 400, TEGO® Glide 406, TEGO® Glide 410,TEGO® Glide 411, TEGO® Glide 415, TEGO® Glide 420, TEGO® Glide 435,TEGO® Glide 440, TEGO® Glide 450, TEGO® Glide A 115, TEGO® Glide B 1484(can also be used as antifoam and deaerator), TEGO® Flow ATF, TEGO® Flow300, TEGO® Flow 460, TEGO® Flow 425 and TEGO® Flow ZFS 460. Suitableradiation-curable lubricants and flow auxiliaries, which can also beused to improve the scratch resistance, are the products TEGO® Rad 2100,TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700, whichare likewise obtainable from TEGO.

Such-auxiliaries are also available, for example, from BYK as BYK®-300BYK®-306, BYK®-307, BYK®-310, BYK®-320, BYK®-333, BYK®-341, Byk® 354,Byk® 361, Byk® 361 N, BYK® 388.

Such-auxiliaries are also available, for example, from 3M as FC4430®.

Such-auxiliaries are also available, for example, from Cytonix asFluorN® 561 or FluorN® 562.

Such-auxiliaries are also available, for example, from Merck KGaA asTivida® FL 2300 and Tivida® FL 2500

The auxiliaries in group c2) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 2.0% byweight, based on the total weight of the polymerisable LC material.

In group c3), the radiation-curing auxiliaries include, in particular,polysiloxanes having terminal double bonds which are, for example, aconstituent of an acrylate group. Such auxiliaries can be crosslinked byactinic or, for example, electron radiation. These auxiliaries generallycombine a number of properties together. In the uncrosslinked state,they can act as antifoams, deaerators, lubricants and flow auxiliariesand/or substrate wetting auxiliaries, while, in the crosslinked state,they increase, in particular, the scratch resistance, for example ofcoatings or films which can be produced using the compositions accordingto the invention. The improvement in the gloss properties, for exampleof precisely those coatings or films, is regarded essentially as aconsequence of the action of these auxiliaries as antifoams, deaeratorsand/or lubricants and flow auxiliaries (in the uncrosslinked state).

Examples of suitable radiation-curing auxiliaries are the products TEGO®Rad 2100, TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad2700 available from TEGO and the product BYK®-371 available from BYK.

Thermally curing auxiliaries in group c3) contain, for example, primaryOH groups, which are able to react with isocyanate groups, for exampleof the binder.

Examples of thermally curing auxiliaries, which can be used, are theproducts BYK®-370, BYK®-373 and BYK®-375 available from BYK.

The auxiliaries in group c3) are optionally employed in a proportion offrom about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the polymerisable LC material.

The substrate wetting auxiliaries in group c4) serve, in particular, toincrease the wettability of the substrate to be printed or coated, forexample, by printing inks or coating compositions, for examplecompositions according to the invention. The generally attendantimprovement in the lubricant and flow behaviour of such printing inks orcoating compositions has an effect on the appearance of the finished(for example crosslinked) print or coating.

A wide variety of such auxiliaries are commercially available, forexample from Tego as TEGO® Wet KL 245, TEGO® Wet 250, TEGO® Wet 260 andTEGO® Wet ZFS 453 and from BYK as BYK®-306, BYK®-307, BYK®-310,BYK®-333, BYK®-344, BYK®-345, BYK®-346 and Byk®-348.

The auxiliaries in group c4) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 1.5% byweight, based on the total weight of the liquid-crystalline composition.

The wetting and dispersion auxiliaries in group c5) serve, inparticular, to prevent the flooding and floating and the sedimentationof pigments and are therefore, if necessary, suitable in particular inpigmented compositions.

These auxiliaries stabilize pigment dispersions essentially throughelectrostatic repulsion and/or steric hindrance of the pigment particlescontaining these additives, where, in the latter case, the interactionof the auxiliary with the ambient medium (for example binder) plays amajor role.

Since the use of such wetting and dispersion auxiliaries is commonpractice, for example in the technical area of printing inks and paints,the selection of a suitable auxiliary of this type generally does notpresent the person skilled in the art with any difficulties, if they areused.

Such wetting and dispersion auxiliaries are commercially available, forexample from Tego, as TEGO® Dispers 610, TEGO® Dispers 610 S, TEGO®Dispers 630, TEGO® Dispers 700, TEGO® Dispers 705, TEGO® Dispers 710,TEGO® Dispers 720 W, TEGO® Dispers 725 W, TEGO® Dispers 730 W, TEGO®Dispers 735 W and TEGO® Dispers 740 W and from BYK as Disperbyk®,Disperbyk®-107, Disperbyk®-108, Disperbyk®-110, Disperbyk®-111,Disperbyk®-115, Disperbyk®-130, Disperbyk®-160, Disperbyk®-161,Disperbyk®-162, Disperbyk®-163, Disperbyk®-164, Disperbyk®-165,Disperbyk®-166, Disperbyk®-167, Disperbyk®-170, Disperbyk®-174,Disperbyk®-180, Disperbyk®-181, Disperbyk®-182, Disperbyk®-183,Disperbyk®-184, Disperbyk®-185, Disperbyk®-190, Anti-Terra®-U,Anti-Terra®-U 80, Anti-Terra®-P, Anti-Terra®-203, Anti-Terra®-204,Anti-Terra®-206, BYK®-151, BYK®-154, BYK®-155, BYK®-P 104 S, BYK®-P 105,Lactimon®, Lactimon®-WS and Bykumen®.

The amount of the auxiliaries in group c5) used on the mean molecularweight of the auxiliary. In any case, a preliminary experiment istherefore advisable, but this can be accomplished simply by the personskilled in the art.

The hydrophobicizing agents in group c6) can be used to givewater-repellent properties to prints or coatings produced, for example,using compositions according to the invention. This prevents or at leastgreatly suppresses swelling due to water absorption and thus a changein, for example, the optical properties of such prints or coatings. Inaddition, when the composition is used, for example, as a printing inkin offset printing, water absorption can thereby be prevented or atleast greatly reduced.

Such hydrophobicizing agents are commercially available, for example,from Tego as Tego® Phobe WF, Tego® Phobe 1000, Tego® Phobe 1000 S, Tego®Phobe 1010, Tego® Phobe 1030, Tego® Phobe 1010, Tego® Phobe 1010, Tego®Phobe 1030, Tego® Phobe 1040, Tego® Phobe 1050, Tego® Phobe 1200, Tego®Phobe 1300, Tego® Phobe 1310 and Tego® Phobe 1400.

The auxiliaries in group c6) are optionally employed in a proportion offrom about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the polymerisable LC material.

Further adhesion promoters from group c7) serve to improve the adhesionof two interfaces in contact. It is directly evident from this thatessentially the only fraction of the adhesion promoter that is effectiveis that located at one or the other or at both interfaces. If, forexample, it is desired to apply liquid or pasty printing inks, coatingcompositions or paints to a solid substrate, this generally means thatthe adhesion promoter must be added directly to the latter or thesubstrate must be pre-treated with the adhesion promoters (also known aspriming), i.e. this substrate is given modified chemical and/or physicalsurface properties.

If the substrate has previously been primed with a primer, this meansthat the interfaces in contact are that of the primer on the one handand of the printing ink or coating composition or paint on the otherhand. In this case, not only the adhesion properties between thesubstrate and the primer, but also between the substrate and theprinting ink or coating composition or paint play a part in adhesion ofthe overall multilayer structure on the substrate.

Adhesion promoters in the broader sense which may be mentioned are alsothe substrate wetting auxiliaries already listed under group c4), butthese generally do not have the same adhesion promotion capacity.

In view of the widely varying physical and chemical natures ofsubstrates and of printing inks, coating compositions and paintsintended, for example, for their printing or coating, the multiplicityof adhesion promoter systems is not surprising.

Adhesion promoters based on silanes are, for example,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,3-aminopropylmethyldiethoxysilane,N-aminoethyl-3-aminopropyltrimethoxysilane,N-aminoethyl-3-aminopropylmethyldimethoxysilane,N-methyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane,3-methacryloyloxypropyltrimethoxysilane,3-glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane,3-chloropropyltrimethoxysilane and vinyltrimethoxysilane. These andother silanes are commercially available from Huls, for example underthe tradename DYNASILAN®.

Corresponding technical information from the manufacturers of suchadditives should generally be used or the person skilled in the art canobtain this information in a simple manner through correspondingpreliminary experiments.

However, if these additives are to be added as auxiliaries from groupc7) to the polymerisable LC materials according to the invention, theirproportion optionally corresponds to from about 0 to 5.0% by weight,based on the total weight of the polymerisable LC material. Theseconcentration data serve merely as guidance, since the amount andidentity of the additive are determined in each individual case by thenature of the substrate and of the printing/coating composition.

Corresponding technical information is usually available from themanufacturers of such additives for this case or can be determined in asimple manner by the person skilled in the art through correspondingpreliminary experiments.

The auxiliaries for improving the scratch resistance in group c8)include, for example, the abovementioned products TEGO® Rad 2100, TEGO®Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700, which areavailable from Tego.

For these auxiliaries, the amount data given for group c3) are likewisesuitable, i.e. these additives are optionally employed in a proportionof from about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the liquid-crystalline composition.

Examples that may be mentioned of further light, heat and/or oxidationstabilizers are the following:

alkylated monophenols, such as 2,6-di-tert-butyl-4-methylphenol,2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol,2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol,2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which have alinear or branched side chain, for example 2,6-dinonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol and mixtures of thesecompounds, alkylthiomethylphenols, such as2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol and2,6-didodecylthiomethyl-4-nonylphenol,

Hydroquinones and alkylated hydroquinones, such as2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydrocrainone, 2,6-diphenyl-4-octadecyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate and bis(3,5-di-tert-butyl-4-hydroxyphenyl)adipate,

Tocopherols, such as α-tocopherol, β-tocopherol, γ-tocopherol,6-tocopherol and mixtures of these compounds, and tocopherolderivatives, such as tocopheryl acetate, succinate, nicotinate andpolyoxyethylenesuccinate (“tocofersolate”),

hydroxylated diphenyl thioethers, such as2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis(3,6-di-sec-amylphenol) and4,4′-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide,

Alkylidenebisphenols, such as2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecyl-mercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecyl-mercaptobutaneand 1,1,5,5-tetrakis(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane,

O-, N- and S-benzyl compounds, such as3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether, octadecyl4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide andisooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate,

aromatic hydroxybenzyl compounds, such as1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethyl-benzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethyl-benzeneand 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol,

Triazine compounds, such as2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate and1,3,5-tris(2-hydroxyethyl)isocyanurate,

Benzylphosphonates, such as dimethyl2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate and dioctadecyl5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate,

Acylaminophenols, such as 4-hydroxylauroylanilide,4-hydroxystearoylanilide and octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate,

Propionic and acetic esters, for example of monohydric or polyhydricalcohols, such as methanol, ethanol, n-octanol, i-octanol, octadecanol,1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol,neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethyleneglycol, pentaerythritol, tris(hydroxyethyl)isocyanurate,N,N′-bis(hydroxyethyl)oxalamide, 3-thiaundecanol, 3-thiapentadecanol,trimethylhexanediol, trimethylolpropane and4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]-octane,

Propionamides based on amine derivatives, such asN,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamineand N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine,

Ascorbic acid (Vitamin C) and ascorbic acid derivatives, such asascorbyl palmitate, laurate and stearate, and ascorbyl sulfate andphosphate,

Antioxidants based on amine compounds, such asN,N′-diisopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenylenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octyl-substituted diphenylamine, such asp,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis[4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine,tert-octyl-substituted N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butyl/tert-octyldiphenylamine, a mixture of mono- anddialkylated nonyldiphenylamine, a mixture of mono- and dialkylateddodecyldiphenylamine, a mixture of mono- and dialkylatedisopropyl/isohexyldiphenylamine, a mixture of mono- and dialkylatedtert-butyldiphenylamine, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- and dialkylatedtert-butyl/tert-octylphenothiazine, a mixture of mono- and dialkylatedtert-octylphenothiazine, N-allylphenothiazine,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine,bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,2,2,6,6-tetramethylpiperidin-4-one and2,2,6,6-tetramethylpiperidin-4-ol,

Phosphines, Phosphites and phosphonites, such as triphenylphosninetriphenylphosphite, diphenyl alkyl phosphite, phenyl dialkyl phosphite,tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite,distearyl pentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl pentaerythritoldiphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,diisodecyloxy pentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butylphenyl))pentaerythritol diphosphite, tristearylsorbitol triphosphite,tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylenediphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocine,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocine,bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite andbis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite,

2-(2′-Hydroxyphenyl)benzotriazoles, such as2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole,2-(3,5′-bis-(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, amixture of2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole,2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole and2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-ylphenol];the product of complete esterification of2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazolewith polyethylene glycol 300;

sulfur-containing peroxide scavengers and sulfur-containingantioxidants, such as esters of 3,3′-thiodipropionic acid, for examplethe lauryl, stearyl, myristyl and tridecyl esters, mercaptobenzimidazoleand the zinc salt of 2-mercaptobenzimidazole, dibutylzincdithiocarbamates, dioctadecyl disulfide and pentaerythritoltetrakis(p-dodecylmercapto)propionate,

2-hydroxybenzophenones, such as the 4-hydroxy, 4-methoxy, 4-octyloxy,4-decycloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxy and2′-hydroxy-4,4′-dimethoxy derivatives,

Esters of unsubstituted and substituted benzoic acids, such as4-tert-butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol,benzoylresorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate,hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate,octadecyl-3,5-di-tert-butyl-4-hydroxybenzoate and2-methyl-4,6-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate,

Acrylates, such as ethyl α-cyano-β,β-diphenylacrylate, isooctylα-cyano-β, β-diphenylacrylate, methyl α-methoxycarbonylcinnamate, methylα-cyano-β-methyl-p-methoxycinnamate,butyl-α-cyano-β-methyl-p-methoxycinnamate andmethyl-α-methoxycarbonyl-p-methoxycinnamate, sterically hindered amines,such as bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(2,2,6,6-tetramethylpiperidin-4-yl)succinate,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)-n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate,the condensation product of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, the condensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethylpiperidin-4-yl)nitrilotriacetate,tetrakis(2,2,6,6-tetramethylpiperidin-4-yl)1,2,3,4-butanetetracarboxylate,1,1′-(1,2-ethylene)bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)succinate, thecondensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensation product of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidin-4-yl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the condensation product of2-chloro-4,6-di(4-n-butylamino-1,2,2,6,6-pentamethylpiperidin-4-yl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]-decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethylpiperidin-4-yl)pyrrolidine-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethylpiperidin-4-yl)pyrrolidine-2,5-dione,a mixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, the condensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, the condensation productof 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine,4-butylamino-2,2,6,6-tetramethylpiperidine,N-(2,2,6,6-tetramethylpiperidin-4-yl)-n-dodecylsuccinimide,N-(1,2,2,6,6-pentamethylpiperidin-4-yl)-n-dodecylsuccinimide,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4.5]-decane,the condensation product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro-[4.5]decaneand epichlorohydrin, the condensation products of4-amino-2,2,6,6-tetramethylpiperidine with tetramethylolacetylenediureasandpoly(methoxypropyl-3-oxy)-[4(2,2,6,6-tetramethyl)piperidinyl]-siloxane,

Oxalamides, such as 4,4′-dioctyloxyoxanilide, 2,2′-diethoxyoxanilide,2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide,N,N′-bis(3-dimethylaminopropyl)oxalamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, and mixtures of ortho-,para-methoxy-disubstituted oxanilides and mixtures of ortho- andpara-ethoxy-disubstituted oxanilides, and

2-(2-hydroxyphenyl)-1,3,5-triazines, such as2,4,6-tris-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyl-1,3,5-triazine,2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxypropoxy)phenyl]-1,3,5-triazineand 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine.

In another preferred embodiment the polymerisable LC material comprisesone or more specific antioxidant additives, preferably selected from theIrganox® series, e.g. the commercially available antioxidantsIrganox®1076 and Irganox®1010, from Ciba, Switzerland.

In another preferred embodiment, the polymerisable LC material comprisesa combination of one or more, more preferably of two or morephotoinitiators, for example, selected from the commercially availableIrgacure® or Darocure® (Ciba AG) series, in particular, Irgacure 127,Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 817, Irgacure 907,Irgacure 1300, Irgacure, Irgacure 2022, Irgacure 2100, Irgacure 2959, orDarcure TPO, further selected from the commercially available OXE02(Ciba AG), NCI 930, N1919T (Adeka), SPI-03 or SPI-04 (Samyang).

The concentration of the polymerisation initiator(s) as a whole in thepolymerisable LC material is preferably from 0.5 to 10%, very preferablyfrom 0.8 to 8%, more preferably 1 to 6%.

Preferably, the polymerisable LC material comprises besides one or morecompounds of formula TRI,

-   -   a) one or more di- or multireactive polymerisable mesogenic        compounds,    -   b) optionally one or more monoreactive polymerisable mesogenic        compounds,    -   c) optionally one or more antioxidative additives,    -   d) optionally one or more adhesion promotors,    -   e) optionally one or more surfactants,    -   f) optionally one or more mono-, di- or multireactive        polymerisable non-mesogenic compounds,    -   g) optionally one or more dyes showing an absorption maximum at        the wavelength used to initiate photo polymerisation,    -   h) optionally one or more chain transfer agents,    -   i) optionally one or more stabilizers,    -   j) optionally one or more lubricants and flow auxiliaries, and    -   k) optionally one or more diluents,    -   l) optionally a non-polymerisable nematic component.

More preferably, the polymerisable LC material comprises,

-   -   a) one or more compounds of formula TRI,    -   b) optionally one or more compound of formula S1,    -   c) one or more, preferably two or more, direactive polymerisable        mesogenic compounds, preferably in an amount, if present at all,        of 10 to 90% by weight, very preferably 15 to 75% by weight,        preferably selected from the compounds of formula DRMa-1,    -   d) optionally one or more, preferably two or more, monoreactive        polymerisable mesogenic compounds, preferably in an amount of 10        to 95% by weight, very preferably 25 to 85%, preferably selected        from compounds of formulae MRM-1 and/or MRM-7,    -   e) optionally one or more compounds of formula ND in the        preferably in an amount of 1 to 50%, very preferably from 1 to        40%.    -   f) optionally one or more antioxidative additives, preferably        selected from esters of unsubstituted and substituted benzoic        acids, in particular Irganox®1076, and if present, preferably in        an amount of 0.01 to 2% by weight, very preferably 0.05 to 1% by        weight,    -   g) optionally one or more lubricants and flow auxiliaries,        preferably selected from BYK®388, FC 4430 and/or Fluor N 562,        and if present, preferably in an amount of 0.1 to 5% by weight,        very preferably 0.2 to 3% by weight, and    -   h) optionally one or more diluents, preferably selected from        n-dodecanol, if present, preferably in an amount of 0.1 to 5% by        weight, very preferably 0.2 to 3% by weight, and

The invention further relates to a method of preparing a polymer film by

-   -   providing a layer of a polymerisable LC material as described        above and below onto a substrate,    -   polymerising the polymerisable components of the polymerisable        LC material by photopolymerisation, and    -   optionally removing the polymerised LC material from the        substrate and/or optionally providing it onto another substrate.

It is also possible to dissolve the polymerisable LC material in asuitable solvent.

In another preferred embodiment, the polymerisable LC material comprisesone or more solvents, which are preferably selected from organicsolvents. The solvents are preferably selected from ketones such asacetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutylketone or cyclohexanone; acetates such as methyl, ethyl or butyl acetateor methyl acetoacetate; alcohols such as methanol, ethanol or isopropylalcohol; aromatic solvents such as toluene or xylene; alicyclichydrocarbons such as cyclopentane or cyclohexane; halogenatedhydrocarbons such as di- or trichloromethane; glycols or their esterssuch as PGMEA (propyl glycol monomethyl ether acetate), γ-butyrolactone.It is also possible to use binary, ternary or higher mixtures of theabove solvents.

In case the polymerisable LC material contains one or more solvents, thetotal concentration of all solids, including the RMs, in the solvent(s)is preferably from 10 to 60%.

This solution is then coated or printed onto the substrate, for exampleby spin-coating, printing, or other known techniques, and the solvent isevaporated off before polymerisation. In most cases, it is suitable toheat the mixture in order to facilitate the evaporation of the solvent.

The polymerisable LC material can be applied onto a substrate byconventional coating techniques like spin coating, bar coating or bladecoating. It can also be applied to the substrate by conventionalprinting techniques which are known to the expert, like for examplescreen printing, offset printing, reel-to-reel printing, letter pressprinting, gravure printing, rotogravure printing, flexographic printing,intaglio printing, pad printing, heat-seal printing, ink-jet printing orprinting by means of a stamp or printing plate.

Suitable substrate materials and substrates are known to the expert anddescribed in the literature, as for example conventional substrates usedin the optical films industry, such as glass or plastic. Especiallysuitable and preferred substrates for polymerisation are polyester suchas polyethyleneterephthalate (PET) or polyethylenenaphthalate (PEN),polyvinylalcohol (PVA), polycarbonate (PC) triacetylcellulose (TAC), orcyclo olefin polymers (COP), or commonly known color filter materials,in particular triacetylcellulose (TAC), cyclo olefin polymers (COP), orcommonly known colour filter materials.

The polymerisable LC material preferably exhibits a uniform alignmentthroughout the whole layer. Preferably the polymerisable LC materialexhibits a uniform planar or a uniform homeotropic alignment.

The Friedel-Creagh-Kmetz rule can be used to predict whether a mixturewill adopt planar or homeotropic alignment, by comparing the surfaceenergies of the RM layer and the substrate:

If γ_(RM)>γ_(s) the reactive mesogenic compounds will displayhomeotropic alignment, If γ_(RM)<γ_(s) the reactive mesogenic compoundswill display homogeneous alignment.

When the surface energy of a substrate is relatively low, theintermolecular forces between the reactive mesogens are stronger thanthe forces across the RM-substrate interface. Therefore, reactivemesogens align perpendicular to the substrate (homeotropic alignment) inorder to maximise the intermolecular forces.

Homeotropic alignment can also be achieved by using amphiphilicmaterials; they can be added directly to the polymerisable LC material,or the substrate can be treated with these materials in the form of ahomeotropic alignment layer. The polar head of the amphiphilic materialchemically bonds to the substrate, and the hydrocarbon tail pointsperpendicular to the substrate. Intermolecular interactions between theamphiphilic material and the RMs promote homeotropic alignment. Commonlyused amphiphilic surfactants are described above.

Another method used to promote homeotropic alignment is to apply coronadischarge treatment to plastic substrates, generating alcohol or ketonefunctional groups on the substrate surface. These polar groups caninteract with the polar groups present in RMs or surfactants to promotehomeotropic alignment.

When the surface tension of the substrate is greater than the surfacetension of the RMs, the force across the interface dominates. Theinterface energy is minimised if the reactive mesogens align parallelwith the substrate, so the long axis of the RM can interact with thesubstrate. One way planar alignment can be promoted is by coating thesubstrate with a polyimide layer, and then rubbing the alignment layerwith a velvet cloth.

Other suitable planar alignment layers are known in the art, like forexample rubbed polyimide or alignment layers prepared by photoalignmentas described in U.S. Pat. Nos. 5,602,661, 5,389,698 or U.S. Pat. No.6,717,644.

In general, reviews of alignment techniques are given for example by I.Sage in “Thermotropic Liquid Crystals”, edited by G. W. Gray, John Wiley& Sons, 1987, pages 75-77; and by T. Uchida and H. Seki in “LiquidCrystals—Applications and Uses Vol. 3”, edited by B. Bahadur, WorldScientific Publishing, Singapore 1992, pages 1-63. A further review ofalignment materials and techniques is given by J. Cognard, Mol. Cryst.Liq. Cryst. 78, Supplement 1 (1981), pages 1-77.

For the production of the polymer films according to the invention, thepolymerisable compounds in the polymerisable LC material are polymerisedor crosslinked (if one compound contains two or more polymerisablegroups) by in-situ photopolymerisation.

The photopolymerisation can be carried out in one step. It is alsopossible to photopolymerise or crosslink the compounds in a second step,which have not reacted in the first step (“end curing”).

In a preferred method of preparation the polymerisable LC material iscoated onto a substrate and subsequently photopolymerised for example byexposure to actinic radiation as described for example in WO 01/20394,GB 2,315,072 or WO 98/04651.

Photopolymerisation of the LC material is preferably achieved byexposing it to actinic radiation. Actinic radiation means irradiationwith light, like UV light, IR light or visible light, irradiation withX-rays or gamma rays, or irradiation with high-energy particles, such asions or electrons. Preferably, polymerisation is carried out by photoirradiation, in particular with UV light. As a source for actinicradiation, for example a single UV lamp or a set of UV lamps can beused. When using a high lamp power the curing time can be reduced.Another possible source for photo radiation is a laser, like e.g. a UVlaser, an IR laser, or a visible laser.

The curing time is dependent, inter alia, on the reactivity of thepolymerisable LC material, the thickness of the coated layer, the typeof polymerisation initiator and the power of the UV lamp. The curingtime is preferably ≤5 minutes, very preferably ≤3 minutes, mostpreferably ≤1 minute. For mass production, short curing times of ≤30seconds are preferred.

A suitable UV radiation power is preferably in the range from 5 to 200mWcm-2, more preferably in the range from 50 to 175 mWcm⁻² and mostpreferably in the range from 100 to 150 mWcm⁻².

In connection with the applied UV radiation and as a function of time, asuitable UV dose is preferably in the range from 25 to 7200 mJcm⁻² morepreferably in the range from 500 to 7200 mJcm⁻² and most preferably inthe range from 3000 to 7200 mJcm⁻².

Photopolymerisation is preferably performed under an inert gasatmosphere, preferably in a heated nitrogen atmosphere, but alsopolymerisation in air is possible.

Photopolymerisation is preferably performed at a temperature from 1 to70° C., more preferably 5 to 50° C., even more preferably 15 to 30° C.

The polymerised LC film according to the present invention has goodadhesion to plastic substrates, in particular to TAC, COP, and colourfilters. Accordingly, it can be used as adhesive or base coating forsubsequent LC layers which otherwise would not well adhere to thesubstrates.

The preferred thickness of a polymerised LC film according to thepresent invention is determined by the optical properties desired fromthe film or the final product. For example, if the polymerised LC filmdoes not mainly act as an optical layer, but e.g. as adhesive, aligningor protection layer, its thickness is preferably not greater than 1 μm,in particular not greater than 0.5 μm, very preferably not greater than0.2 μm.

For example, uniformly homeotropic or planar aligned polymer films ofthe present invention can be used as retardation or compensation filmsfor example in LCDs to improve the contrast and brightness at largeviewing angles and reduce the chromaticity. They can be used outside theswitchable liquid-crystalline cell in an LCD, or between the substrates,usually glass substrates, forming the switchable liquid-crystalline celland containing the switchable liquid-crystalline medium (in cellapplication).

For optical applications of the polymer film, it preferably has athickness of from 0.5 to 10 μm, very preferably from 0.5 to 5 μm, inparticular from 0.5 to 3 μm.

The optical retardation (δ(λ)) of a polymer film as a function of thewavelength of the incident beam (λ) is given by the following equation(7):

δ(λ)=(2πΔn·d)/λ  (7)

wherein (Δn) is the birefringence of the film, (d) is the thickness ofthe film and λ is the wavelength of the incident beam.

According to Snellius law, the birefringence as a function of thedirection of the incident beam is defined as

Δn=sin Θ/sin Ψ  (8)

wherein sin Θ is the incidence angle or the tilt angle of the opticalaxis in the film and sin Ψ is the corresponding reflection angle.

Based on these laws, the birefringence and accordingly opticalretardation depends on the thickness of a film and the tilt angle ofoptical axis in the film (cf. Berek's compensator). Therefore, theskilled expert is aware that different optical retardations or differentbirefringence can be induced by adjusting the orientation of theliquid-crystalline molecules in the polymer film.

The birefringence (Δn) of the polymer film according to the presentinvention is preferably in the range from 0.01 to 0.30, more preferablein the range from 0.01 to 0.25 and even more preferable in the rangefrom 0.01 to 0.16.

The optical retardation as a function of the thickness of the polymerfilm according to the present invention is less than 200 nm, preferableless than 180 nm and even more preferable less than 150 nm.

The polymer film of the present invention can also be used as alignmentfilm for other liquid-crystalline or RM materials. For example, they canbe used in an LCD to induce or improve alignment of the switchableliquid-crystalline medium, or to align a subsequent layer ofpolymerisable LC material coated thereon. In this way, stacks ofpolymerised LC films can be prepared.

In summary, the polymerised LC films and polymerisable LC materialsaccording to the present invention are useful in optical elements likepolarisers, compensators, alignment layer, circular polarisers or colourfilters in liquid crystal displays or projection systems, decorativeimages, for the preparation of liquid crystal or effect pigments, andespecially in reflective films with spatially varying reflectioncolours, e.g. as multicolour image for decorative, information storageor security uses, such as non-forgeable documents like identity orcredit cards, banknotes etc.

The polymerised LC films according to the present invention can be usedin displays of the transmissive or reflective type. They can be used inconventional OLED displays or LCDs, in particular LCDs of the DAP(deformation of aligned phases) or VA (vertically aligned) mode, likee.g. ECB (electrically controlled birefringence), CSH (colour superhomeotropic), VAN or VAC (vertically aligned nematic or cholesteric)displays, MVA (multi-domain vertically aligned) or PVA (patternedvertically aligned) displays, in displays of the bend mode or hybridtype displays, like e.g. OCB (optically compensated bend cell oroptically compensated birefringence), R-OCB (reflective OCB), HAN(hybrid aligned nematic) or pi-cell (π-cell) displays, furthermore indisplays of the TN (twisted nematic), HTN (highly twisted nematic) orSTN (super twisted nematic) mode, in AMD-TN (active matrix driven TN)displays, or in displays of the IPS (in plane switching) mode which arealso known as ‘super TFT’ displays. Especially preferred are VA, MVA,PVA, OCB, and pi-cell displays.

The polymerisable LC material and polymer films according to the presentinvention are especially useful for a 3D display as described in EP 0829744, EP 0887666 A2, EP 0887692, U.S. Pat. Nos. 6,046,849, 6,437,915 andin “Proceedings o the SID 20^(th) International Display ResearchConference, 2000”, page 280. A 3D display of this type comprising apolymer film according to the invention is another object of the presentinvention.

The present invention is described above and below with particularreference to the preferred embodiments. It should be understood thatvarious changes and modifications might be made therein withoutdeparting from the spirit and scope of the invention.

Many of the compounds or mixtures thereof mentioned above and below arecommercially available. All of these compounds are either known or canbe prepared by methods which are known per se, as described in theliterature (for example in the standard works such as Houben-Weyl,Methoden der Organischen Chemie [Methods of Organic Chemistry],Georg-Thieme-Verlag, Stuttgart), to be precise under reaction conditionswhich are known and suitable for said reactions. Use may also be madehere of variants which are known per se, but are not mentioned here.

It will be appreciated that variations to the foregoing embodiments ofthe invention can be made while still falling within the scope of theinvention. Alternative features serving the same, equivalent, or similarpurpose may replace each feature disclosed in this specification, unlessstated otherwise. Thus, unless stated otherwise, each feature disclosedis one example only of a generic series of equivalent or similarfeatures.

All of the features disclosed in this specification may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. In particular, thepreferred features of the invention are applicable to all aspects of theinvention and may be used in any combination. Likewise, featuresdescribed in non-essential combinations may be used separately (not incombination).

It will be appreciated that many of the features described above,particularly of the preferred embodiments, are inventive in their ownright and not just as part of an embodiment of the present invention.Independent protection may be sought for these features in addition toor alternative to any invention presently claimed.

The invention will now be described in more detail by reference to thefollowing working examples, which are illustrative only and do not limitthe scope of the invention.

EXAMPLES General Procedure

The mixtures are dissolved in to 33.3% solids in toluene/cyclohexanone(7/3). The solution is spin coated at 2000 rpm on a raw glass substratewhich is coated with rubbed PI. The film is annealed at 68° C. for 120second and cured under a N2 atmosphere using a Fusion conveyor, H Bulb(95% power, 10 m/min. ˜300 mJ/cm², UV B).

The film is laminated to a pressure sensitive adhesive and left with anopen surface so the total film stack is glass/polymer film/pressuresensitive adhesive and the film is subjected to the durabilityexperiment.

To measure the difference of the retardation and dispersion of the curedfilm in dependence of UV stress, Axoscan ellipsometer is used todetermine the initial retardation and dispersion. The film is thenstressed with Suntest XLS+ (350 W/m²) for 198 h. After the test theretardation profile and dispersion is determined again. The durabilityis quantified by the difference in R_(in) and the dispersion(R_(450/550)) before and after the UV test.

Utilized Compound of Formula TRI

Example 1

The following mixture M1 is prepared in accordance with the followingtable:

Compound %-w/w RM-1 FluorN 561 0.42 RM-2 Irganox 1076 0.12 RM-3

23.53 RM-4

11.68 RM-5

28.75 RM-6

34.00 RM-7

1.50

The mixture M1 is divided into 3 parts and the parts are mixed with acombination of 900 ppm

and 0.9% TRI-a

a combination of 1500 ppm

and 0.9% TRI-a, respectively, whereas one portion remains unchanged.

Each mixture is dissolved, coated and cured as described above and thechange in retardation and dispersion is determined before after thesuntest. The results are summarized in the following table:

Host Mixture Stabilizer Amount ΔR_(in) [%] ΔR_((450/550)) [%] M1 — — 9.05.4 M1 Stab 1/  900 ppm 5.6 4.6 TRI-a 0.9 % M1 Stab 2/ 1500 ppm 4.8 3.7TRI-a 0.9 %

Example 2

The following mixture M2 is prepared in accordance with the followingtable:

No. % w/w RM-1 0.42 RM-2 0.12 RM-3 20.53 RM-4 11.68 RM-5 32.75 RM-633.00 RM-7 1.50

The mixture M2 is divided into 3 parts and the parts are mixed with acombination of 900 ppm Stab 1 and 0.9% TRI-a, a combination of 1500 ppmStab 2 and 0.9% TRI-a, respectively, whereas one portion remainsunchanged.

Each mixture is dissolved, coated and cured as described above and thechange in retardation and dispersion is determined before after thesuntest. The results are summarized in the following table:

Host Mixture Stabilizer Amount ΔR_(in) [%] ΔR_((450/550)) [%] M1 — — 9.36.2 M1 Stab 1/  900 ppm 6.5 4.8 TRI-a 0.9 % M1 Stab 2/ 1500 ppm 6.3 4.0TRI-a 0.9 %

Example 3

The following mixture M3 is prepared in accordance with the followingtable:

Compound %-w/w RM-1 0.42 RM-2 0.12 RM-3 23.29 RM-4 11.56 RM-5 28.46 RM-633.66 RM-7 1.50

0.90

0.90

Example 4

The following mixture M4 is prepared in accordance with the followingtable:

Compound %-w/w RM-1 0.42 RM-2 0.12 RM-3 20.32 RM-4 11.56 RM-5 32.42 RM-632.67 RM-7 1.50

0.90

0.90

Example 5

The following mixture M5 is prepared in accordance with the followingtable:

Compound %-w/w RM-1 0.42 RM-2 0.12 RM-3 23.28 RM-4 11.55 RM-5 28.44 RM-633.64 RM-7 1.50

0.90

0.15

Example 6

The following mixture M6 is prepared in accordance with the followingtable:

Compound %-w/w RM-1 0.42 RM-2 0.12 RM-3 20.31 RM-4 11.55 RM-5 32.40 RM-632.65 RM-7 1.50

0.90

0.15

Example 7

The mixture M1 is divided into 5 parts and the parts are mixed with1.1%, 1.35%, 1.5% and 1.8% of compound TRI-a, respectively, whereas oneportion remains unchanged.

Each mixture is dissolved, coated and cured as described above and thedispersion is determined. The results are summarized in the followingtable:

Host Mixture Stabilizer Amount R_((450/550)) M1 — — 0.87 M1 TRI-a 1.1%0.85 M1 TRI-a 1.35% 0.84 M1 TRI-a 1.5% 0.84 M1 TRI-a 1.8% 0.83

As can be seen from the values for R_(450/550), the utilization ofcompounds of formula TRI leads to mixtures with stronger negativedispersions. As a consequence, for example, less amounts of expensivecompounds of formula RM-6 are required to achieve a comparable negativedispersion by the utilization of compounds of formula TRI.

1. Polymerizable LC material comprising at least one di- ormultireactive mesogenic compound and one or more compounds of formulaTRI,

wherein R¹ to R⁹ each denote independently from another a hydrogen atom,a hydroxy group, a halogen atom, an alkyl group having 1 to 20 carbonatoms, an alkenyl group having 3 to 20 carbon atoms, an alkoxy grouphaving 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbonatoms; R^(a) denotes a straight chain or branched alkyl having 1 to 20,which is optionally mono- or polysubstituted by F, Cl, Br, I or CN andin which, in addition, one or more non-adjacent CH₂ groups may each bereplaced, independently of one another, by —O—, —S—, —NH—, —NR^(xx)—,—SiR^(xx)R^(yy)—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—,—NR^(xx)—CO—O—, —O—CO—NR^(xx)—, —NR^(xx)—CO—NR^(yy)—, —CH═CH— or —C≡C—in such a way that O and/or S atoms are not linked directly to oneanother, and R^(xx) and R^(yy) each and independently of one another,denote H or alkyl having 1 to 12 C atoms.
 2. Polymerisable LC materialaccording to claim 1, wherein at least one di- or multireactivemesogenic compound is selected of formula DRMP¹-Sp¹-MG-Sp²-P²  DRM wherein P¹ and P² independently of each otherdenote a polymerisable group, Sp¹ and Sp² independently of each otherare a spacer group or a single bond, and MG is a rod-shaped mesogenicgroup, which is preferably selected of formula MG-(A¹-Z¹)_(n)-A²-  MG wherein A¹ and A² denote, in case of multipleoccurrence independently of one another, an aromatic or alicyclic group,which optionally contains one or more heteroatoms selected from N, O andS, and is optionally mono- or polysubstituted by L¹, L¹ is P-Sp-, F, Cl,Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)OR⁰⁰,—C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅, optionally substituted silyl, aryl orheteroaryl with 1 to 12 C atoms, straight chain or branched alkyl,alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy oralkoxycarbonyloxy with 1 to 12, C atoms, wherein one or more H atoms areoptionally replaced by F or Cl, R⁰⁰ and R⁰⁰⁰ independently of each otherdenote H or alkyl with 1 to 12 C-atoms, Z¹ denotes, in case of multipleoccurrence independently of one another, —O—, —S—, —CO—, —COO—, —OCO—,—S—CO—, —CO—S—, —O—COO—, —CO—NR⁰⁰—, —NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰,—NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—,—OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—,—CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C≡C—,—CH═CH—COO—, —OCO—CH═CH— or a single bond, Y¹ and Y² independently ofeach other denote H, F, Cl or CN, n is 1, 2, 3 or 4, and n1 is aninteger from 1 to
 10. 3. Polymerisable LC material according to claim 1,wherein at least one direactive mesogenic compound is selected of fromthe following formulae,

wherein P⁰ is, in case of multiple occurrence independently of oneanother, an acryl, methacryl, oxetane, epoxy, vinyl, heptadiene,vinyloxy, propenyl ether or styrene group, L has on each occurrenceidentically or differently one of the meanings given for L¹ in formulaDRM, r is 0, 1, 2, 3 or 4, x and y are independently of each other 0 oridentical or different integers from 1 to 12, z is each andindependently, 0 or 1, with z being 0 if the adjacent x or y is
 0. 4.Polymerisable LC material according to claim 1, comprising at least onemonoreactive mesogenic compound, which is selected from formula MRM,P¹-Sp¹-MG-R  MRM wherein P¹, Sp¹ and MG have the meanings as given informula DRM, R is F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,—C(═O)NR^(x)R^(y), —C(═O)X, —C(═O)OR^(x), —C(═O)R^(y), —NR^(x)R^(y),—OH, —SF₅, optionally substituted silyl, straight chain or branchedalkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy oralkoxycarbonyloxy with 1 to 12 C atoms, wherein one or more H atoms areoptionally replaced by F or Cl, X is halogen, preferably F or Cl, andR^(x) and R^(y) are independently of each other H or alkyl with 1 to 12C-atoms.
 5. Polymerisable LC material according to claim 1, wherein atleast one monoreactive mesogenic compound is selected from the followingformulae,

wherein P⁰ is, in case of multiple occurrence independently of oneanother, an acryl, methacryl, oxetane, epoxy, vinyl, heptadiene,vinyloxy, propenyl ether or styrene group, L has on each occurrenceidentically or differently one of the meanings given for L¹ in formulaDRM, r is 0, 1, 2, 3 or 4, x and y are independently of each other 0 oridentical or different integers from 1 to 12, z is each andindependently, 0 or 1, with z being 0 if the adjacent x or y is 0 R⁰ isalkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 or more, preferably 1 to 15C atoms or denotes Y⁰, Y⁰ is F, Cl, CN, NO₂, OCH₃, OCN, SCN, SF₅, ormono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms, Z⁰is —COO—, —OCO—, —CH₂CH₂—, —CF₂O—, —OCF₂—, —CH═CH—, —OCO—CH═CH—,—CH═CH—COO—, or a single bond, A⁰ is, in case of multiple occurrenceindependently of one another, 1,4-phenylene that is unsubstituted orsubstituted with 1, 2, 3 or 4 groups L, or trans-1,4-cyclohexylene, uand v are independently of each other 0, 1 or 2, w is 0 or 1, andwherein the benzene and naphthalene rings can additionally besubstituted with one or more identical or different groups L. 6.Polymerisable LC material according to claim 1 one, comprising one ormore compounds of formula ND,

wherein U^(1,2) are independently of each other selected from

including their mirror images, wherein the rings U¹ and U² are eachbonded to the group —(B)_(q)— via the axial bond, and one or twonon-adjacent CH₂ groups in these rings are optionally replaced by Oand/or S, and the rings U¹ and U² are optionally substituted by one ormore groups L, Q^(1,2) are independently of each other CH or SiH, Q³ isC or Si, B is in each occurrence independently of one another —C≡C—,—CY¹═CY²— or an optionally substituted aromatic or heteroaromatic group,Y^(1,2) are independently of each other H, F, Cl, CN or R⁰, q is aninteger from 1 to 10, preferably including, 2, 3, 4, 5, 6 or 7, A¹⁻⁴ areindependently of each other selected from non-aromatic, aromatic orheteroaromatic carbocyclic or heterocyclic groups, which are optionallysubstituted by one or more groups R⁵, and wherein each of-(A¹-Z¹)_(m)—U¹—(Z²-A²)_(n)- and -(A³-Z³)_(o)—U²—(Z⁴-A⁴)_(p)- does notcontain more aromatic groups than non-aromatic groups and preferablydoes not contain more than one aromatic group, Z¹⁻⁴ are independently ofeach other —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR⁰—, —NR⁰—CO—,—NR⁰—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—,—SCF₂—, —CH₂CH₂—, —(CH₂)₃—, —(CH₂)₄—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—,—CH═CH—, —CY¹═CY²—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰—, —C≡C—, —CH═CH—COO—,—OCO—CH═CH—, CR⁰R⁰⁰ or a single bond, R⁰ and R⁰⁰ are independently ofeach other H or alkyl with 1 to 12 C-atoms, m and n are independently ofeach other 0, 1, 2, 3 or 4, and p are independently of each other 0, 1,2, 3 or 4, R¹⁻⁵ are independently of each other identical or differentgroups selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN,—C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H,—SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, P-Sp-, optionally substituted silyl, orcarbyl or hydrocarbyl with 1 to 40 C atoms that is optionallysubstituted and optionally comprises one or more hetero atoms, or denoteP or P-Sp-, or are substituted by P or P-Sp-, wherein the compoundscomprise at least one group R¹⁻⁵ denoting or being substituted by P orP-Sp-, P is a polymerisable group, Sp is a spacer group or a singlebond,
 7. Polymerisable LC material according to claim 1, wherein theproportion of di- or multireactive polymerisable mesogenic compounds isin the range from 5 to 99% by weight.
 8. Polymerisable LC materialaccording to claim 1, wherein the proportion of monoreactivepolymerizable mesogenic compounds is in the range from 5 to 80% byweight.
 9. Polymerisable LC material according to claim 1, comprisingoptionally one or more additives selected from the group consisting of,surfactants, further stabilisers, catalysts, sensitizers, inhibitors,chain-transfer agents, co-reacting monomers, reactive thinners,surface-active compounds, lubricating agents, wetting agents, dispersingagents, hydrophobing agents, adhesive agents, flow improvers, degassingor defoaming agents, deaerators, diluents, reactive diluents,auxiliaries, colourants, dyes, pigments and nanoparticles.
 10. Processfor the preparation of the polymerisable LC material according to claim1 comprising the steps of mixing one or more compounds of formulae S0,S1 or S2 with at least one di- or multireactive mesogenic compound. 11.Process for the preparation of the of a polymer film by providing alayer of a polymerisable LC material according to claim 1 onto asubstrate, photopolymerising the polymerisable LC material, andoptionally removing the polymerised LC material from the substrateand/or optionally providing it onto another substrate.
 12. Polymer filmobtainable from a polymerisable LC material according to claim 1 by aprocess comprising the steps providing a layer of the polymerisable LCmaterial onto a substrate, photopolymerising the LC material, andoptionally, removing the polymerised LC material from the substrateand/or optionally providing it onto another substrate.
 13. Polymer filmaccording to claim 12, characterized in that the LC material isuniformly aligned.
 14. A method comprising including a polymerisable LCmaterial according to claim 1 or a polymer film obtained therefrom indevices with optical, electro optical, information storage, decorativeand security applications, including devices with liquid crystaldisplays, 3D displays, projection systems, polarisers, compensators,alignment layers, circular polarisers, colour filters, decorativeimages, liquid crystal pigments, reflective films with spatially varyingreflection colours, multicolour images and non-forgeable documents,including identity cards, credit cards and banknotes.
 15. Opticalcomponent or device, polariser, patterned retarder, compensator,alignment layer, circular polariser, colour filter, decorative image,liquid crystal lens, liquid crystal pigment, reflective film withspatially varying reflection colours, multicolour image for decorativeor information storage, comprising a polymerisable LC material accordingto claim 1, or a polymer film obtained therefrom.